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Glossary

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A
• AGS
  • The American Gem Society (AGS) is a trade association of retail jewelers, independent appraisers, suppliers, and selective industry members, which was founded in 1934 by Robert M. Shipley, who also founded the (GIA). Members are held to a high code of ethics with emphasis on consumer protection and education.
    The Society is based in Las Vegas, Nevada, along with the affiliated American Gem Society Laboratories (AGSL) (founded in 1996) and the American Gem Society Advanced Instruments Division (founded in 2004).
    The Society trains and certifies jewelers, gemologists, and jewelry appraisers. Diamond grading is the specialty of the American Gem Society Laboratories and the Society has developed its own cut, color, and clarity standards.
    
    
    
• Alloy
  • An alloy is a homogenous mixture or metallic solid solution composed of two or more elements.[1] Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal (heat treatment) history. Alloys usually have different properties from those of the component elements.
    
    
• Alluvial Stone
  • A stone that has been transported by water and deposited in seas, lakes or stream beds. Many gems, including diamonds, are found in alluvial deposits.
    
    
• American Cut
  • Those proportions and facet angles calculated mathematically by Marcel Tolkowsky to produce maximum brilliancy consistent with a high degree of fire in a round diamond brilliant are considered by many diamond men to constitute the ideal cut. These figures, computed as a percentage of the girdle diameter, are as follows: total depth, 59.3% (without provision for girdle thickness); crown depth, 16.2%; pavilion depth, 43.1%. The bezel angle is 34° 30' and the pavilion angle is 40° 45'. Girdle thickness as a percentage of the girdle's diameter varies with size. The larger the stone, the smaller the percentage for a medium girdle. The variation is from about 1% to 3%
    
    
• Angles
  • In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.[1] The magnitude of the angle is the "amount of rotation" that separates the two rays, and can be measured by considering the length of circular arc swept out when one ray is rotated about the vertex to coincide with the other (see "Measuring angles", below). Where there is no possibility of confusion, the term "angle" is used interchangeably for both the geometric configuration itself and for its angular magnitude (which is simply a numerical quantity).
    
    
• Antwerp Diamond Bourse
  • Antwerp has been home to a flourishing diamond industry for the past 500 years. Today, it has become the world's most important diamond centre, importing over 80% of the world's rough and polished diamonds before being distributed further.
    The Antwerp diamond centre is located a hundred yards from the railway station. A multitude of diamond merchants trade in rough and polished diamonds worth billions of dollars. Their activities are based on tradition. Strict rules have been established which have regulated the industry for the past five centuries, giving the merchants the opportunity to put their unparalleled professional expertise at the disposal of clients from all over the world.
    
    
• Appraisal
  • Appraisal is a type of decision method applied to a project, programme or policy that takes into account a wide range of costs and benefits, denominated in monetary terms or for which a monetary equivalent can be estimated. Economic Appraisal is a key tool for achieving value for money and satisfying requirements for decision accountability. It is a systematic process for examining alternative uses of resources, focusing on assessment of needs, objectives, options, costs, benefits, risks, funding, affordability and other factors relevant to decisions.
    
    
• Asscher Cut
  • In 1902 Joseph Asscher upheld his father's reputation for skill and innovation by designing the original Asscher cut. This emblematic cut was the first signature cut to be patented. The Asscher Diamond Company held its exclusive patent until the Second World War and saw strong sales internationally.
    
    

B


• Baguette
  • The baguette cut—which accentuates a diamond's luster and downplays its fire—was all the rage during the Art Deco period .
    
    
• Bail
  • A bail is a component of certain types of jewelry, mostly necklaces, that is used to attach a pendant. The bail is normally placed in the center of the necklace where the pendant hangs. Some bails are made so a pendant can be attached after the necklace production is completed. This way, a necklace design can be mass-produced for multiple companies and the pendants can be attached after the necklaces are shipped to them.
    
    
• Band
  • A circular band worn as a type of ornamental jewelry around a finger; it is the most common current meaning of the word ring. Other types of metal bands worn as ornaments are also called rings, such as arm rings and neck rings.
    
    
• Bangle
  • Bangles are circular in shape, and, unlike bracelets, are not flexible. The word is derived from Hindi bungri (glass).[1] They are made of numerous precious as well as non-precious materials such as gold, silver, platinum, glass, wood, ferrous metals, plastic, etc. Bangles are part of traditional Indian jewelry. They are usually worn in pairs by women, one or more on each arm. Most Indian women prefer wearing either gold or glass bangles or combination of both. Inexpensive bangles made from plastic are slowly replacing those made by glass, but the ones made of glass are still preferred at traditional occasions such as marriages and on festivals. The designs range from simple to intricate handmade designs, often studded with precious and semi-precious stones such as diamonds, gems and pearls. Sets of expensive bangles made of gold and silver make a jingling sound. The imitation jewelry, tend to make a tinny sound when jingled.
    
    
• Bar Setting
  • Individual metal bars are set perpendicular to the ring, separating the gemstones. The metal is molded around a gem to lock it in place.
    
    
• Barrel Clasp
  • Barrel clasps are a type of fastener typically seen on pieces of jewelry, such as necklaces or bracelets. Each end of a barrel clasp is attached to one end of a chain, rope, thread, or other material and fits together to complete a connection and secure the jewelry around the body. Barrel clasps are barrel shaped and make one of two types of connections. They either screw together on tiny threads or they lock together with magnetic force.
    
    
• Bead Setting
  • Bead setting is a generic term for setting a stone directly into metal using gravers, also called burins, which are essentially tiny chisels. A hole is drilled directly into the metal surface, and then a ball burr is used to make a concave depression just the size of the stone.
    
    
• Bearded Girdle
  • But no matter how hard a Diamond is, it's still easy to chip the edge of it. The edges are the weakest part of the Diamond. Called the Girdle, the Edge of the Diamond is thin and vulnerable. Prongs are spaced around your Diamond's edge to help protect the Girdle from chipping, let alone losing your Diamond. A good strike at the right angle can take a section of the Girdle away. Sometimes a good hard strike can fracture your Diamond and turn it into pieces of cloudy sections. Diamonds that have been worn for years and years get tons of little small chips all the way around the Girdle. These fine fractures are termed "Bearded Girdles"
    
    
• Bezel
  • The earliest technique of attaching stones to jewelry was bezel setting. A bezel is a strip of metal bent into the shape and size of the stone and then soldered to the piece of jewelry. Then the stone is inserted into the bezel and the metal rubbed over the stone, holding it in place. This method works well for either cabochon or faceted stones.
    
    
• Bezel Facets
  • The facet located on the crown, or top portion, of a diamond. Jewelers call this the 'kite' facet because of its shape.
    
    
• Black Diamond
  • When a diamond is dark gray, a very dark green or truly black, it is referred to in the trade as a "black diamond." Such a stone may be opaque to nearly semitransparent.
    
    
• Blemish
  • Any surface imperfection on a fashioned diamond; e.g., a nick, knot, scratch, abrasion, minor crack or cavity, or poor polish. Also, a natural or an extra facet, visible on or through the crown, usually is considered a blemish.
    
    
• Blood Diamonds
  • In relation to diamond trading, conflict diamond (also called a converted diamond, blood diamond, hot diamond, or a war diamond) refers to a diamond mined in a war zone and sold to finance an insurgency, invading army's war efforts, or a warlord's activity, usually in Africa[1] where around two-thirds of the world's diamonds are extracted.[2]
    
    
• Blue Book
  • The CIBJO's operations include the development of the Blue Book, a three-part publication outlining terminology, classification, and ethical guidelines (i.e., disclosure of treatments and synthetics) for coloured gemstones, diamonds, and pearls. Each part is coordinated by a separate commission.
    
    
• Blue Diamond
  • A diamond with a distinctly blue body color, even thought very light in tone, is a fancy diamond. Diamond that are blue in both daylight and incandescent light are rare, although fluorescence stones that show a blue color in daylight are comparatively common. A blue color may also be induced artificially.
    
    
• Blueground
  • A miner's nickname for "kimberlite," the rock that contains diamonds in the South African pipe mines.
    
    
• Blue White
  • Blue-white refers to the fluorescence that results in natural light, which contains ultraviolet wavelengths. This blue fluorescence actually makes a colorless diamond look a little oily or milky in sunlight and decreases its value. However, for stones with a faint yellow color, a moderate amount of fluorescence can make it look whiter because it cancels some of the yellow.
    
    
• Body Colour
  • The color of a diamond as observed when examined under a diffused light against a hueless background free from surrounding reflections. The diffused light eliminates glaring reflections and dispersion, which would otherwise confuse the color determination.
    
    
• Bombarded Diamond
  • A diamond that has been subjected to bombardment by fast electrons, neutrons, deuterons, etc. The purpose of bombardment is to make the color of the stone more attractive and desirable.
    
    
• Bort
  • Bort or boart is a term used in the diamond industry to refer to shards of gem-grade/quality diamonds. In the manufacturing and heavy industries, "bort" is used to describe dark, imperfectly formed/crystallized diamonds of varying levels of opacity. The lowest grade, "crushing bort", is crushed by steel mortars and used to make industrial-grade abrasive grits. Small bort crystals are used in drill bits. The Democratic Republic of the Congo provides 75% of the world supply of crushing bort.
    
    
• Bourse
  • French, meaning an exchange or meeting place where merchants transact business. The word is often used for a diamond dealers club or organization.
    
    
• Bow Tie Effect
  • An effect caused by a shadowy area visible in some fancy shapes, caused by light leaking out the bottom of the Diamond
    
    
• Box Chain
  • A box chain is made up of square links - links that are wide and square (hence resembling a box) - that are connected to create a smooth chain.
    
    
• Box Clasp
  • A very popular for multi-strand bracelets clasp consisting of a box, tongue, snag, and trigger. Although there are several variations to the clasp's looks, all of them work on the same principal.
    
    
• Break Facets or Girdle Facets
  • The 32 triangular facets that adjoin the girdle of a round brilliant-cut stone, 16 above and 16 below.
• Bridal Set
  • The traditional set of two rings that fit together- the engagement ring and the wedding band. A Trio Set is three rings in a matched set, an engagement and wedding band for the bride and coordinating wedding band for the groom.
• Brilliance
  • Refers to the amount of light returned to the eye from the interior of a gem and is mainly a function of refractive index, proportions and transparency.
    
    
• Brilliant Cut
  • The last part of polishing diamond, where the brillianteer adds twenty-four facets to the crown and sixteen facets to the pavilion.
    
    
• Brillianteering
  • The last part of polishing diamond, where the brillianteer adds twenty-four facets to the crown and sixteen facets to the pavilion.
    
    
• Briolette
  • Describes a shape and a style of faceting (gemstone cutting) Briolettes are usually an oval or pear shape drop bead (top drilled or side drilled) with its entire surface cut in angular facets for a beautiful sparkle.
    
    
• Broker
  • A broker is a party that arranges transactions between a buyer and a seller, and gets a commission when the deal is executed. A broker who also acts as a seller or as a buyer becomes a principal party to the deal. Distinguish agent: one who acts on behalf of a principal.
    
    
• Brown Diamond
  • Many people describe brown or brownish diamonds as "champagne" diamonds, presumably because it sounds more exotic, expensive and desirable. Certainly brown is not a "high preference" colour.
    
    
• Bruise
  • Damage consisting of surface crumbling, often accompanied by tiny, root like feathers.
    
    
• Brushed Finish
  • Also known as "satin" finish, is a texturing technique used on jewelry metals where a series of tiny parallel lines are scratched on the surface with a wire brush.
    
    
• Bruting
  • Bruting is the first step in cutting a diamond. Bruting involves shaping the girdle, which gives the stone its basic shape.
    
    
• Bubble
  • Bubbles are spherical or tear-shaped bubbles of gas captured in glass stones. Bubbles can also be found in resins (like plastics and amber), and much less-frequently in minerals (like quartz, emerald, and topaz).
    
    
• Burned Facet
  • This facet may appear whitish, or burnt, as a result of the cutter polishing the facet "against the grain".
    
    
• Byzantine Chain
  • A chain with close-fitting links, creating an intricate design that for ms a tube.
    
    

C


• Cable Chain
  • A chain with round links of the same size.
    
    
• Cabochon Cut
  • The art of rounding a gem without facets into the shape of a highly-polished dome.
    
    
• Cairo Star
  • Cairo star cut. A rarely used, blocky, 74-facet style of brilliant cutting that was developed from the briolette in an attempt to retain maximum weight with a minimum loss of brilliancy.
    
    
• Canary Diamond
  • Diamonds that are golden yellow in color with fluorescence in yellow, golden and orange colors. Also known as fancy yellow.
    
    
• Cape
  • A broad range of diamond color grades that show a distinct yellow tint face up (except for small stones in the top part of the range).
    
    
• Carat (ct)
  • When the word "carat" is applied to gemstones, including diamonds, it means a unit of weight. A carat is equal to one fifth (0.20) of a metric gram.
    
    
• Carat Total Weight (ct.tw)
  • The only Element Furnishing a Gem. It will be noted that the first species considered, diamond, consisted of but a single element, carbon.
    
    
• Carbon
  • The edges are the weakest part of the Diamond. Called the Girdle, the Edge of the Diamond is thin and vulnerable. Prongs are spaced around your Diamond's edge to help protect the Girdle from chipping, let alone losing your Diamond.
    A good strike at the right angle can take a section of the Girdle away. Sometimes a good hard strike can fracture your Diamond and turn it into pieces of cloudy sections.
    Diamonds that have been worn for years and years get tons of little small chips all the way around the Girdle. These fine fractures are termed "Bearded Girdles"
    
    
• Carbonado
  • Carbonado is imperfectly crystallised diamond, usually black or grey, it is usually ground or crushed to use as abrasive or other industrial diamond use.
    
    
• Carbon Pinpoints
  • Miniscule spots internal to a Diamond. A cluster of pinpoints can form a cloud.
    
    
• Carbon Spots
  • These are small, dark-appearing diamond inclusions that, upon close inspection, are usually seen to be clear diamond crystals, clear mineral crystals or cleavages.
    
    
• Cathedral Setting
  • Any surface imThe romance of an elegant cathedral with its arched gables and luxurious curves is captured in every basic cathedral setting, where the band of the ring splits, forming an upper and lower segment with the distinctive arch between them. The lower ring band encircles the finger, while the upper portion of the band arches up to embrace the central mounting and focal diamond or gemstone, which is frequently in a classic tiffany setting. The degree of arch can vary widely, from a subtle split with only a low arch to a wider separation with more elaborate curves reaching for the diamond. perfection on a fashioned diamond; e.g., a nick, knot, scratch, abrasion, minor crack or cavity, or poor polish. Also, a natural or an extra facet, visible on or through the crown, usually is considered a blemish.
    
    
• Cavity
  • A type of inclusion consisting of a large or deep opening in a diamond.
    
    
• Centenary
  • The De Beers Centenary Diamond is, at 273.85 carats (54.77 g), the third-largest diamond to have been produced in the Premier Mine. The Centenary Diamond is rated in color as grade D color by the Gemological Institute of America, which is the highest grade of colourless diamond and is internally and externally flawless. It was named the Centenary Diamond as it was presented in the rough for the Centennial Celebration of De Beers Consolidated Mines on May 11, 1988. The Centenary Diamond was unveiled in final form in May 1991.
    
    
• Center Stone
  • The central, dominant stone in a piece of jewelry set with multiple stones.
    
    
• Certificates, Certification
  • More accurately known as diamond grading reports, are commonly provided with the purchase of a significant piece of diamond jewelry such as a diamond Engagement Ring or a diamond Three Stone Ring.
    
    
• Certified
  • A certified diamond's quality is guaranteed, and this makes it more valuable than an uncertified stone. The certificate verifies a diamond's identity and value, and it will be recognized by all gemologists. Below are examples of GIA Grading Reports.
    
    
• Certified Gemologist
  • A title awarded by the American Gem Society. To qualify, a person must study colored stones and their identification and diamond grading and appraising.
    
    
• Chain
  • Chains involve a number of connected loops, links, rings, or beads ordered one after the other. This is usually a beginning step in creating bracelets or necklaces.
    
    
• Champagne Diamond
  • A trade term describing a light yellow diamond with green or brown overtone but lacks the intensity to be a Fancy Color Diamond.
    
    
• Channel Setting
  • Channel setting is a technique whereby gemstones are set side-by-side with their girdles held between two long tracks of precious metal.
    
    
• Chemical Vapour Deposition
  • Chemical vapor deposition (CVD) is a chemical process used to produce high-purity, high-performance solid materials. The process is often used in the semiconductor industry to produce thin films. In a typical CVD process, the wafer (substrate) is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber.
    
    
• Chiffre
  • A three-faceted shield-shaped rose cut with a flat, unfaceted base.
    
    
• Chip
  • Shallow break on a diamond which extends from a facet junction or girdle edge and is larger or deeper than a nick.
    
    
• Choker
  • A choker is a type of necklace that fits tightly around the neck. Chokers are from 14" to 16" in length.
    
    
• Clarity
  • Clarity is possibly the most important of the factors affecting the quality and price of any diamond. Diamonds of all colours can be vary attractive. Diamonds of all different cuts look good, and not many diamonds are very badly proportioned.
    
    
• Clarity Enhanced, Clarity Enhancement
  • A broad term for gemstones that covers many different treatments or procedures that remove or diminish flaws, thereby enhancing the clarity.
    
    
• Clasp
  • A clasp is a fastener that can open and close, attaching two things together (for example, the two ends of a necklace, or a pin to a garment).
    
    
• Claw Setting
  • A claw setting is one in which a series of metal prongs (called claws) holds a stone securely in a setting (the claws grips the stone just above the girdle of the stone), with no metal directly under the stone (it is an open setting).
    
    
• Clean
  • Frequently misused term to describe a diamond with slight imperfections. Can also be used to describe a diamond with internal imperfections. Use is prohibited by the FTC unless the stone qualifies as "perfect" as described by the Commission.
    
    
• Cleavage
  • Cleavage refers to a gemstone's tendency to break parallel to certain flat planes. Cleavage is rarely entirely on one level or plane but can have a step-like appearance.
    
    
• Cleavage Crack
  • A break parallel to a cleavage plane. It is characterized by a two-dimensional nature; intersections with facets are usually straight lines.
    
    
• Closed Culet
  • A culet on a diamond that is too small to be resolved with the unaided eye and that can be seen only with difficulty under 10x. The term is rarely used to refer to a pavilion point or ridge with no "culet."
    
    
• Closed Table
  • A term used by some diamond men to designate a small table diameter. However, its interpretation and use varies. It may refer to a diameter less than the American cut 53% (of the girdle diameter) or, more frequently, to a table smaller than about 60%, because so many of the stones cut today have tables well over that figure.
    
    
• Cloud
  • A grouping of a number of extremely tiny inclusions that are too small to be distinguishable from one another, even under magnification.
    
    
• Cloudy Texture or Cloud Texture
  • A group of tiny white inclusions, composed of minute hollow spaces, or very small patches of tiny crystals or other impurities that produce a cottony or clouded appearance in a n otherwise highly transparent diamond. A cloud may be so minute that it is difficult to see under 10X, or it may be large enough to deprive the entire stone of brilliancy.
    
    
• Cluster Setting
  • This setting surrounds larger center stone with several smaller stones. It is designed to create a beautiful larger ring from many smaller stones.
    
    
• Coated Diamond, Coating
  • A diamond colored by a surface coating which masks the true body-color; the coating may be extensive (entire pavilion, for example), but is more often limited to one or two pavilion facets or a spot on the girdle.
    
    
• Cognac
  • A more desirable color than the dark brown it shows an orange-brown mixture similar to the color of cognac.
    
    
• Collet, Collets
  • Collet is a style of setting used to hold gemstones in place. It is also known as claw and consists of a 'Bezel' and 'Prong'.
    
    
• Colourimeter
  • A colorimeter is a device used in colorimetry. In scientific fields the word generally refers to the device that measures the absorbance of particular wavelengths of light by a specific solution. This device is most commonly used to determine the concentration of a known solute in a given solution by the application of the Beer-Lambert law, which states that the concentration of a solute is proportional to the absorbance.
    
    
• Colour
  • When grading diamonds 'color' refers to the absence of color in a diamond. The rating scale begins at D (meaning colorless) and ends at Z (meaning having a lot of color).
    
    
• Colour Grading
  • a system of grading diamond colours based on their colourlessness (for white diamonds) or their spectral hue, depth of colour and purity of colour (for fancy colour diamonds). For white diamonds, HRD and IGI use a grading system which runs from D (totally colourless) to Z (light yellow).
    
    
• Comfort Fit
  • The rounded finish on a ring's interior, designed to provide additional comfort for long-wear.
    
    
• Commercial White
  • A misleading term that is used to mean not white, but slightly off color. Often misused, the AGS and the FTC prohibits use of this term.
    
    
• Commercially Clean
  • The common meaning of this term is "reasonably free from inclusions." IF a diamond were without flaws or blemishes, logically, it would be called flawless or perfect.
    
    
• Corundum
  • Corundum is crystalline aluminum oxide, Al2O3, second hardest on Mohs Scale, and one of the most popular (and expensive) of gem minerals. Ruby is red corundum; all other colors are Sapphire.
    
    
• Craftsmanship
  • An artisan (from Italian: artigiano) is a skilled manual worker who makes items that may be functional or strictly decorative, including furniture, clothing, jewellery, household items, and tools.
    
    
• Created
  • A gemstone made in a laboratory with the same properties as a genuine gemstone. Also known as synthetic.
    
    
• Critical Angle
  • Greatest angle measured from normal at which light can be refracted out of a stone. Small angle at which light is totally internally reflected.
    
    
• Crown
  • The part of a facetted gemstone above the girdle.
    
    
• Crown Angle
  • The angle at which a diamond''s bezel facets (or, on emerald cuts, the row of concentric facets) intersect the girdle plane.
    
    
• Crown Height
  • The crown height expressed as a percentage of the average girdle diameter.
    
    
• Crystal
  • Crystal is mostly glass mixed with lead - the magic ingredient that gives crystal its sparkle. Lead makes the glass heavier and allows the glass to be cut and given facets, making it glint and twinkle - like a diamond.
    
    
• Crystal Structure
  • In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry. Patterns are located upon the points of a lattice, which is an array of points repeating periodically in three dimensions. The points can be thought of as forming identical tiny boxes, called unit cells, that fill the space of the lattice. The lengths of the edges of a unit cell and the angles between them are called the lattice parameters
    
    
• Cube
  • One of the seven basic forms in the highest symmetry (hexoctahedral) class of the cubic, or isometric, crystal system. It has six square faces that make 90° angles with one another, each of which intersects one crystallographic axis and is parallel to the other two. Gem-quality cube-shaped diamond crystals are so rare as to be regarded as collector's items.
    
    
• Cubic System
  • The Isometric crystal system which consists of three axes, each of equal length and perpendicular to others.
    
    
• Cubic Zirconia
  • The diamond substitute known as cubic zirconia was found naturally formed in the 1930's but today it is simulated in a laboratory environment, as natural forms are no longer easily found.
    
    
• Culet
  • The culet (pronounced cue-let) is the small area at the bottom of a diamond's pavilion. The culet can be a point or a very small facet sitting parallel to the table.
    
    
• Cullinan, Cullinan I, Cullinan II
  • Cullinan Diamond is a pear shaped diamond that is acknowledged to be the largest rough gem-quality diamond ever discovered in the world and has a body mass of 3,106.75 carats (621.35 g).
    
    
• Curb Link Chain
  • A chain with oval links that are twisted to lie flat.
    
    
• Cushion Cut
  • A cushion cut stone is a square or rectangular cut with rounded corners and multiple facets for maximum light refraction.
    
    
• Cut
  • The cut of a diamond refers, first of all, to its shape. Diamonds are cut into many different shapes, reflecting not only popular taste but the proportions and quality of the rough stone.
    
    
• Cut, Fair
  • While still capturing some sparkle, this cut lacks brilliance and proportion when compared to the Good and Very Good cuts.
    
    
• Cut, Good
  • Good cut grade of a diamond helps reflect light to obtain a good amount of brilliance, though not equal to the Excellent or Very Good cut. Thus it demands a much lesser price.
    
    
• Cut, Ideal
  • This is when the diamond is perfectly proportioned with the highest grade of polish and symmetry. These stones reflect just about all the light that enters. They are the most brilliant, rare and one of the finest diamonds.
    
    
• Cut, Poor
  • Poorly cut diamonds with proportions and finish that make them look relatively lifeless to the eye.
    
    
• Cut, Super Ideal
  • The term Hearts and Arrows is used to describe the visual effect achieved in a round Super Ideal Cut diamond with perfect symmetry and angles that exhibit a crisp and complete pattern of Hearts & Arrows. When viewed under a special magnifying viewer, a complete and precise visual pattern of 8 hearts is seen while looking down through the pavilion, and 8 arrows can be seen when viewing the stone in the table up position.
    
    
• Cut, Very Good
  • Very good cut diamonds reflect most of the light that enters them, dispersing a good deal of brilliance. With these diamonds, the diamond cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond.
    
    
• Cutter
  • Any workman engaged in the cutting and polishing of diamonds.
    
    
• Cutting
  • The way in which the shape and facet arrangement of a diamond or gemstone is designed.
    
    
• CVD
  • Chemical vapor deposition of diamond or CVD is a method of producing synthetic diamond by creating the circumstances necessary for carbon atoms in a gas to settle on a substrate in crystalline form.
    
    

D


• DCLA
  • The Diamond Certification Laboratory of Australia (DCLA) is one of the world's foremost independent diamond grading and certification laboratories.
    
    
• De Beers
  • The De Beers Groups is one of the largest diamond trading companies providing exquisite collection of diamonds to the clients. All diamonds in De beers are characterized by beauty, fire, life and brilliance.
    
    
• Deep Cut
  • When a diamond is cut too deep, it will lose or leak light through the side or bottom. This results in less brilliance and value.
    
    
• Density
  • Density is defined as the ratio of the mass of an object to its volume.
    Density should correctly be expressed in units of "unit mass per unit volume", e.g. grams per cubic centimetre. The figure quoted is often the same as that for specific gravity. For those who are unsure what "mass" means, consider it to be the same as "weight", you will not be far out.
    
    
• Depth
  • Depth is the distance from the very top of a diamond or gemstone to the very bottom of a diamond or gemstone.
    
    
• Depth Percentage
  • Depth percentage, which expresses how deep the diamond is in comparison to how wide it is. This depth percentage of a diamond is important to its brilliance and value.
    
    
• Depth & Table Percentages
  • The table percentage of a diamond represents the ratio of table width to overall stone width. Like depth percentage, the luster of the stone is directly affected by its table percentage.
    
    
• Design
  • Jewelry that is often designed to cater to a certain trend or fad. Designer jewelry can also refer to a line created by a specific jewelry craftsman.
    
    
• Diamantaire
  • Anyone professionally involved with diamond manufacturing or marketing.
    
    
• Diamantiferous
  • Diamond-bearing ground.
    
    
• Diameter
  • The Diameter is a type of measurement used for circles (or other round objects). The diameter measurement is used in the piercing industry to determine the size of a ring used in piercings, to ensure that the correct size is worn.
    
    
• Diamond
  • Diamond is the eternal and most precious gemstone of the world. The name diamond was derived from an ancient Greek word, 'adamas' which means 'invincible'. Diamond belongs to the class of native metals and is a member of the group of Carbon.
    
    
• Diamond Certificate
  • A certificate issued to a diamond by the Gemological Institute of America (GIA) or others, upon successfully passing the diamond-grading. The Certificate gives a complete and detailed description of the diamond, listing the 4C's.
    
    
• Diamondoid
  • A diamondoid, in the context of building materials for nanotechnology components, most generally refers to structures that resemble diamond in a broad sense: namely, strong, stiff structures containing dense, 3-D networks of covalent bonds, formed chiefly from first and second row atoms with a valence of three or more. Examples of diamondoid structures would include crystalline diamond, sapphire, and other stiff structures similar to diamond but with various atom substitutions which might include N, O, Si, S, and so forth. Sp2-hybridized carbon structures that – in contrast to sp3-hybridized carbon in diamond – arrange in planar sheets ("graphene" sheets) are sometimes also included in the class of diamondoid materials for nanotechnology, e.g., graphite, carbon nanotubes consisting of sheets of carbon atoms rolled into tubes, spherical buckyballs and other graphene structures.
    
    
• Diamond Gauge
  • An instrument that is used to measure a diamond's length, width and depth in millimeters.
    
    
• Diamond Grading Report
  • Documents issued by gemological laboratories that evaluate a diamond's cut, clarity, color and carat.
    
    
• Diamond Saw
  • A diamond-charged blade used as a cutting edge in fashioning colored stones or in various applications in industry.
    
    
• Diamond Sure
  • Well-conceived and highly effective synthetic diamond detection instrument.
    
    
• Diamond Syndicate
  • One of the names by which De Beers, with its inter-related companies, is known. Many diamond syndicates have been formed at various periods of time, to purchase large important diamonds.
    
    
• Diamond Trading Company, Ltd
  • A De Beers-owned company (DTC) that sells rough diamonds to diamond merchants.
    
    
• Diamond Tweezers
  • Tweezers with rounded ends, corrugated tips and rather a weak spring to hold diamonds and other stones.
    
    
• Diamond View
  • DiamondView works by producing a fluorescence image of a diamond. Specifically, DiamondView uses a camera to display the fluorescence pattern created on the surface of a diamond after it has been exposed to shortwave UV light. Given that the fluorescence colours and patterns from synthetic diamonds differ greatly from those of natural diamonds, DiamondView makes it possible for gemmological laboratories and jewellery professionals to determine whether a diamond is natural or synthetic. In addition, by obtaining a phosphorescence image, DiamondView also makes it possible to detect whether Type II diamonds could be near colourless synthetics.
    
    
• Diamond Wedding Anniversary
  • 60th Wedding Anniversary
    
    
• Diamonique
  • Diamonique is a registered trade mark, belonging to QVC Inc., and the brand name they choose to use for cubic zirconia, a popular diamond simulant.
    
    
• Dimensions
  • In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify each point within it.
    
    
• Direction
  • Direction is the information contained in the relative position of one point with respect to another point without the distance information.
    
    
• Dispersion
  • Dispersion is the difference between the amount of refraction of different colours of light. White light is actually composed of light of all different colours.
    
    
• Dodecahedron
  • A twelve-sided geometric solid. One of the crystal forms found in the Isometric crystal system.
    
    
• Dop
  • A cutter's holding device used while polishing diamond. The dop would be held by the tang. In some automated diamond cutting systems the dop and tang are incorporated into one design.
    
    
• Double Refraction
  • When a ray of light enters a crystal having a Trigonal system in directions other than the optic axis, it splits into two distinct rays. This is known as double refraction.
    
    
• Dresden
  • 41 carats, most likely from India. This pear shaped green diamond's early history is not known. In around 1700 it was in the possession of August the Strong, Duke of Saxony. Kept in the Green Hall in Dresden, hence it's name.
    
    
• Drill, Drills, Drilling
  • As the name specifies, in this step a small hole is created through the stone, such stones are known as beads.
    
    
• Drill Bit
  • Drill bits are cutting tools used to create cylindrical holes.
    
    
• Drop Earrings
  • Drop earrings have a classical appeal in all the ages. From the name we can easily guess that drop earrings are earrings, which drop down from the earlobe.
    
    
• Durability
  • Hardness 10 on Mohs scale. The hardest natural substance. Diamonds can be cut and polished only with other diamonds, and only because of slight directional differences in hardness and a perfect octahedral cleavage.
    
    
• Dutch Rose
  • A typical rose cut diamond has a unique shape and facet arrangement. It has a flat bottom and an elevated pointed dome with triangular facets forming a point. The dome is generally in the shape of a hemisphere or pyramid. The number of triangular facets in a rose cut diamond may vary between 12 to 24. Generally it has a lower tier of triangular facets which in combination with the upper tier, gives the look of a rose bud. The facets in the upper tier are called star facets and the ones in the lower tier are known as the diagonal facets. Usually, the middle portion of a rose cut diamond has six triangular facets, which meet at a point in the center. The outline of this diamond is usually circular but there are oval, hexagonal and pear-shaped domes. The facet arrangement in rose cut diamonds are usually in multiples of six.
    
    

E


• EGL
  • European Gemological Laboratory - EGL has franchises in a number of cities around the world which grade diamonds.
    
    
• Eight Cut
  • This has 8 facets on the upper and lower parts as well, plus the table. It is used for small stones.
    
    
• Element Six
  • Element Six is a subsidiary of De Beers and the world's leading manufacturer and supplier of industrial Diamond supermaterials. Element Six operates globally with its head office registered in Luxembourg, and primary manufacturing facilities in China, Germany, Ireland, Sweden, South Africa and the UK.
    
    
• Emerald
  • Emeralds, like all colored gemstones, are graded using four basic parameters – the four Cs of Connoisseurship: Color, Cut, Clarity and Crystal. The last C, crystal is simply used as a synonym that begins with C for transparency or what gemologists call diaphaneity. Before the 20th century, jewelers used the term water as in "a gem of the finest water" to express the combination of two qualities, color and crystal. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency to be considered a top gem.
    
    
• Emerald Cut
  • A form of "step cutting." It usually is rectangular but sometimes is square, in which case it is known as a square emerald cut. It has rows (steps) of elongated facets on the crown and pavilion, parallel to the girdle, with sets on each of four sides and at the corners. The number of rows, or steps, may vary, although the usual number is three on the crown and three on the pavilion. The emerald cut is seldom used for diamonds in the intermediate color grades, since it tends to emphasize color. It is excellent, however, for colorless stones and when it is desirable to emphasize the color of fancy colors.
    
    
• Engrave
  • To decorate metal by gouging a design with graver's tools; embellishing metal or other material with patterns using a stamping tool or drill. This was a popular technique in mid-Victorian jewelry.
    
    
• Enhancements
  • Gemstone enhancement is defined as any treatment process that is used to improve the appearance, durability or availability of a gemstone.
    
    
• European Cut
  • Style of diamond cutting popular from approximately 1890 to the 1930s typified by a round girdle, a smaller table in relation to the diameter of the stone, and a large culet.
    
    
• Extra Facet
  • An asymmetrical and irregularly placed facet that is not part of the original faceting scheme.
    
    
• Eye Clean
  • A term used to describe a diamond that has no flaws visible to the unaided eye of a diamond expert, usually misused.
    
    

F


• Face
  • A term used for flat or plane surface that make up the exterior form of a crystal.
    
    
• Facet
  • This has 8 facets on tA facet is one of the flat surfaces of a cut stone or glass.
    he upper and lower parts as well, plus the table. It is used for small stones.
    
    
• Faceting
  • Faceting is the cutting and polishing of the surface of a stone.
    
    
• Fancy Coloured Diamond
  • A Diamond that exhibits a strong color, such as yellow, as opposed to an off colored white Diamond. Fancy colored Diamonds can be very expensive and are often highly prized by collectors.
    
    
• Fancy Cut or Fancy Shape
  • A diamond cut in any shape other than round. Fancy cuts include such shapes as baguette, emerald, triangle, pear, princess, oval and marquise.
    
    
• Fancy Diamond
  • Fancy diamond refers to a strong color property of a diamond. A diamond that has a distinctive color, such as red, blue, yellow or any other is called a Fancy Diamond.
    
    
• Feather
  • Feather inclusions (Ftr) are caused by cleavage planes or internal stress fractures that have the appearance of wispy feathers.
    
    
• Filigree
  • Filigree is gold or silver wire that have been twisted into patterns and soldered into place. Openwork filigree is not soldered onto a sheet of metal and is difficult to make. Imitation filigree is made of stamped metal.
    
    
• Fill, Filled, Filling
  • Diamond clarity is sometimes improved and enhanced by filling tiny fractures or feathers with molten glass, much like you would repair a crack in a car's windshield glass.
    
    
• Finding
  • The component parts or materials used in making a piece of jewelry.
    
    
• Finish
  • Refers to the surface quality of a gemstone or piece of jewelry.
    
    
• Fire
  • Fire is the common name for the effect caused by dispersion.
    
    
• Fisheye
  • Diamond with a pavilion depth of less than 40 percent, in which a circular gray reflection of all or part of the girdle appears through the table when the stone is examined face-up.
    
    
• Fishhook Clasp
  • Also called a Hook and Eye Clasp, this fastener has a hook on one end of the chain and a metal loop on the other. The hook fits through the loop to keep the chain together.
    
    
• Fissure
  • A fissure is an elongated fracture or crack in the surface of a diamond.
    
    
• Flat Stone
  • A diamond brilliant with a very thin crown and pavilion.
    
    
• Flaw
  • Flaw refers to any internal or external imperfection on a gemstone and usually includes scratch, feather, fissure, carbon spot, knot, etc.
    
    
• FL or Flawless
  • Flawless is a term used for a gemstone that is without any internal or external flaw when viewed by a trained eye under 10X magnification.
    
    
• Florentine Finish
  • Florentine finish is a surface finish pattern made up of a series of engraved lines crossed lightly by perpendicular lines or cross-hatching.
    
    
• Fluorescence
  • Fluorescence refers to a diamond's tendency to emit a soft colored glow when subjected to ultraviolet light (such as a "black light"). Roughly 30% of diamonds fluoresce to some degree.
    
    
• Flush Setting
  • A setting style in which the entire gemstone is sunk into the metal of the jewelry so that only the top is visible.
    
    
• Four Cs
  • Four important factors that control a diamond's appearance and durability are often lumped together and called the Four Cs: diamond color, clarity, cut and carat weight.
    
    
• Foxtail Chain
  • A foxtail chain is an intricate chain featuring three rows of links braded together.
    
    
• Fracture
  • Fractures are caused mainly by mechanical stresses like pressure or impact and may run in all directions within the diamond.
    
    
• Fracture Fill, Filled, Filling
  • In diamonds, fracture filling entails a molten glass filling that improves clarity. You can get a lot more stone for your money buying fracture filled diamonds, the problem is that the treatment isn't always permanent.
    
    
• French Wire
  • A curved wire which passes through the pierced earlobe and has a catch closure. Used mostly in dangling earrings.
    
    
• Full-cut Brilliant
  • A brilliant-cut diamond or colored stone with the usual total of 58 facets.
    
    
• Fuzzy Girdle or Bearded Girdle
  • Tiny, numerous, hair like fractures extending into the stone.
    
    

G


• Gabrielle Cut
  • The cut was created by, and named for, the master diamond cutter Gabriel S. "Gabi" Tolkowsky, the great-nephew of Marcel Tolkowsky who, as a math student in London in 1919, set the exact parameters for the perfect round brilliant cut with 58. The Gabrielle diamond stands out for its 105 facets (47 more than the ideal cut which has only 58) which allow for an unparalleled brilliance. The cutting style is also known as a "triple brilliant" and is available in classic rounds and all the fancy shapes: the marquise, oval, pear, square or princess (known as carre), emerald and heart. It is available in sizes of .50 carats and up.
    
    
• GAGTL, G.A.G.T.L.
  • Gemmological Association and Gem Testing Laboratory of Great Britain (BUAC)
    
    
• Gauge, Gauges
  • A measuring device for determining diameters, thickness, height, etc.
    
    
• Gem
  • A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.
    
    
• Gem-A
  • The Gemmological Association of Great Britain
    
    
• Gem Defensive Programme
  • Gem Defensive Programme has as it's primary goal, the development of reliable methods to separate natural diamonds from these new synthetic diamonds.
    
    
• Gemologist, Gemmologist
  • A person who has successfully completed recognized courses in gemology and has proven skills in identifying and evaluating gem materials.
    
    
• Gemscope
  • High-resolution diamonds imaging microscopic view of diamonds.
    
    
• Gemscribe
  • GEMScribe is a powerful automatic diamond inscription system which allows you to inscribe on the stone's girdle for any conceived purpose.
    
    
• Gemstone
  • A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.
    
    
• GIA
  • The Gemological Institute of America. The GIA was established in 1931 as a nonprofit educational resource for the gem and jewelry industry.
    
    
• Girdle
  • Girdle is the widest part or outer edge of the gemstone and the dividing line between the crown and pavilion. The girdle can be rough (matt), faceted, polished or unpolished but a polished or faceted girdle doesn't improve a gemstone's grade.
    
    
• Girdle Facets
  • The 32 triangular facets that adjoin the girdle of a round brilliant-cut stone, 16 above and 16 below. Also called upper- and lower-girdle facets, upper- and lower-break facets, top- and bottom-half facets, skew facets or cross facets.
    
    
• Girdle Reflection
  • When a diamond has a pavilion that is too shallow or flat, the girdle is seen reflected in the table.
    
    
• Girdle Thickness
  • The average thickness of the gemstone's girdle, which is the junction between the crown and pavilion of the stone.
    
    
• Girdling
  • Girdling is the process of giving a circular shape to a gemstone. In this process, a gemstone is held in a lathe, or in a cutting machine, and cut or shaped by another diamond or tool, called a sharp.
    
    
• Gold
  • Gold is the most malleable and ductile metal; a single gram can be beaten into a sheet of one square meter, or an ounce into 300 square feet. Gold leaf can be beaten thin enough to become translucent.
    
    
• Golden Jubilee
  • A Golden Jubilee is a celebration held to mark a 50th anniversary.
    
    
• Goods
  • In economics and accounting, a good is a product that can be used to satisfy some desire or need. More narrowly but commonly, a good is a tangible physical product that can be contrasted with a service which is intangible. As such, it is capable of being delivered to a purchaser and involves the transfer of ownership from seller to customer.
    
    
• Grading Report
  • Diamond Grading Reports: There are many recognized gemological laboratories that can grade your diamond for a fee. The most well know is the GIA, Gemological Institute of America.
    
    
• Graduated
  • Graduated refers to a piece of jewelry where the beads start of small at the clasps and then progressively increase in size toward the middle.
    
    
• Grain Center
  • A small area of concentrated crystal structure distortion, usually associated with pinpoints.
    
    
• Grainer
  • An old style term used to describe carat weight in 1/4 carat increments. A two grainer is a 1/2 carat, a 3 grainer is a 3/4 carat, etc.
    
    
• Graining
  • Indications of irregular crystal growth. May appear milky, like faint lines or streaks, or may be colored or reflective.
    
    
• Green Gold
  • Green gold: is a colored gold finish that has a slight green hue due to the addition of silver as an alloy.
    
    
• Gypsy Setting
  • The stone is set into a solid piece of metal by drilling a recess into the metal, placing the stone in the hole and then forming the metal at the edge of the hole back over the stone to secure it.
    
    

H


• Hardness
  • Diamond is renowned for its hardness. Hardness is the measure of a substance's resistance to being scratched, and only a diamond can scratch another diamond. Diamond is the hardest substance known.
    
    
• Hatton Garden
  • Hatton Garden is a street and area near Holborn in London, England. It is most famous for being London's jewellery quarter and centre of the UK diamond trade, but the area is also now home to a diverse range of media and creative businesses.
    
    
• Head
  • Head refers part of the setting that holds the center stone or solitaire in place.
    
    
• Heart-Shaped Diamond
  • A "fancy cut" diamond or stone in the shape of a heart.
    
    
• Heavy (Heavily) Spotted
  • Extremely spotteed diamond.
    
    
• Height
  • The height of a pendant, earring, or other piece of jewellery as measured vertically from the top to the bottom. This measurement is usually a closely estimated average.
    
    
• Herringbone Chain
  • A chain made up of short, flat, slanted parallel links with the direction of the slant alternating row by row resembling the spine of the herring.
    
    
• Hidden Clasp
  • A clasp that has an additional safety. To open, unsnap the safety latch, push down on the tab until it unlocks, and gently pull apart.
    
    
• High-Polish Finish
  • A piece of jewelry that has been polished to a mirror-like finish.
    
    
• Hoop Earrings
  • Hoop earrings are simply earrings in the shape of a hoop or circle.
    
    
• Hope
  • The 45.52 carat steel blue Hope Diamond was found in India back in remote times as a rough crystal weighing 112 carats.
    
    
• HRD
  • 'De Hoge Raad voor Diamant' is a prestigious independent European gemological certification laboratory based in Antwerp, Belgium that began grading diamonds and providing grading reports in 1976. The HRD does not sell diamonds, but acts as a consultant in the grading of precious gems. It is important to note that a grading report provided by any gemological laboratory is NOT a statement of the monetary value of a particular stone (like an appraisal), but a professional opinion that evaluates only its quality.
    
    
• Hue
  • Hue is the term used for the actual color of the spectrum (red, orange, yellow, green, blue, indigo or violet). The more pure a gemstone's hue, the more valuable.
    
    

I


• IGI
  • International Gemological Institute. A laboratory which offers a diamond grading report.
    
    
• Illicit Diamond Buying
  • It has been calculated by persons engaged in the business than 12 per cent. of the fall in the price of rough diamonds which has taken place within the last few years should be set down to the sale of stolen gems, which, to the value of more than 500,000, annually find their way to be markets.
    
    
• Illusion Setting
  • Used for smaller diamonds, this setting supports one or more diamonds in prongs within a larger surface of white gold, which is in turn supported in a larger setting, thus giving the "illusion" of a larger diamond.
    
    
• Imitation
  • Imitation gemstones can be anything that resembles a natural gemstone but does not have the same physical characteristics or chemical composition. These items are usually much less expensive than the natural forms.
    
    
• Incident Ray
  • The 'incident ray' is the ray of light that strikes the surface before reflection, transmission, or absorption.
    
    
• Included or Imperfect
  • An internal flaw, or inclusion, within the diamond crystal.This is a separate crystal within the diamond crystal matrix.It is often simply another diamond crystal.
    
    
• Included Crystal
  • Mineral crystals, such as garnet or peridot, contained inside a diamond.
    
    
• Inclusion
  • In gemstones, an inclusion is any solid, liquid, or gaseous foreign body enclosed in the mineral or rock. The price of Amber can vary greatly based on the type of inclusions and clarity of the stone.
    
    
• Indented Natural
  • The portion of the original rough diamond's surface which is left on the polished diamond dips slightly inward, creating an indentation.
    
    
• Inlaid Setting
  • A portion of the metal setting has been cut away and replaced by a stone. In this setting, the stones are flush with the metal surface.
    
    
• Internal Graining
  • Internal indications of irregular crystal growth. May appear milky, like faint lines or streaks, or may be colored or reflective.
    
    
• Invisible Setting
  • A setting where stones are placed very closely together in a metal framework below the surface so that the metal cannot be seen. Stones sit side-by-side, giving them the appearance of a continuous surface.
    
    
• Iridium
  • Iridium is a metal that is similar to platinum and are commonly alloyed together in order to decrease the cost of a piece of jewelry.
    
    
• Iron
  • Iron is a metal rarely used in jewelry since it is so brittle and lacks luster (except in its mineral forms, pyrite or marcasite). Iron jewelry was popular in Germany in the early 1800's during the war with Napoleon.
    
    
• Irradiated Diamond
  • A diamond which has been exposed to radiation.
    
    

J


• Jeweller's Loupe
  • Loupe is a French word for magnifying glass. It is a small magnifying lens used to examine gemstones. 10X magnification is the standard.
    
    
• Jewellery Cleaner
  • A solution that usually incorporates water and a mild detergent, although many often contain small amounts of ammonia.
    
    
• Jewellery Polishing Cloth
  • Cloth used to clean and polish jewelry safely.
    
    

K


• Karat
  • A measure, from 1 to 24, used to indicate how much of a piece of jewelry is gold content and how much an alloy.
    
    
• Kimberley
  • Kimberley is a city in South Africa, and the capital of the Northern Cape. It is located near the confluence of the Vaal and Orange Rivers. The town has considerable historical significance due its diamond mining past and siege during the Second Boer War. Notable personalities such as Cecil Rhodes made their fortune here and the roots of the De Beers corporation can also be traced to the early days of the mining town.
    
    
• Kimberley Octahedron
  • The Kimberley Octahedron is an uncut diamond discovered in 1964 in South Africa in the Dutoitspan mine, one of the diamond mines situated in the Kimberley region of South Africa. The name of the diamond reflects its place of origin, the internationally renowned diamond producing region where the first diamonds were discovered in 1871.
    
    
• Kimberley Process
  • KPCS was introduced by United Nations General Assembly Resolution 55/56 following recommendations in the Fowler Report. The process was established in 2003 to prevent diamond sales from financing rebellious movements. The certification scheme aims at preventing "blood diamonds" from entering the mainstream rough diamond market. It was set up to assure consumers that by purchasing diamonds they were not financing war and human rights abuses.
    
    
• Kimberlite
  • Kimberlite is a type of potassic volcanic rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.7 g) diamond in 1871 spawned a diamond rush, eventually creating the Big Hole.
    
    
• Knife-edge Girdle
  • A very thin, knife-edge like girdle on a diamond. Not very desirable, since such a girdle is vulnerable to chipping.
    
    
• Knot
  • A knot is a flaw (a mineral inclusion) in a gemstone (usually a diamond) that is at the surface of a gem after polishing. The knot is a small raised bump on the finished gemstone.
    
    
• Kohinoor, Koh-i-noor, Koh-i-nur
  • Persian for "Mountain of Light," one of the world's most famous diamonds, weighing 186 carats until recut in 1852 to 108.93 carats. Dating back 5,000 years, it was found in India, and is presently in the English Crown Jewels.
    
    

L


• Laser Drilled
  • A diamond treatment that involves using a concentrated beam of laser light to drill to a diamond's dark inclusions and disguise or alter them.
    
    
• Laser Drill Hole
  • A tiny tube made by a laser. The surface opening may resemble a pit, while the tube usually looks needle-like.
    
    
• Laser Inscription
  • The laser etched text put on diamond girdle for identification, usually consisting of the grading laboratory initials and the certification number.
    
    
• Latch Earring Back
  • The hinged arm closes and snaps into the U-shaped lock.
    
    
• Leakage
  • Areas that do not return light.
    
    
• Length-to-Width Ratio
  • A comparison of how much longer a diamond is than it is wide, used to analyze the outline of fancy shape diamonds.
    
    
• Light Yellow
  • A trade term used by some dealers to cover a wide range of colors in the low end of the diamond color-grading scale. Stones in the broad classification show a very obvious yellow tint to the unaided eye.
    
    
• Lobster Claw Clasp
  • An interlocking catch with a spring mechanism and a safety lock.
    
    
• Lonsdaleite
  • Lonsdaleite (named in honour of Kathleen Lonsdale), also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with a hexagonal lattice. In nature, it forms when meteorites containing graphite strike the Earth. The great heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified in 1967 from the Canyon Diablo meteorite, where it occurs as microscopic crystals associated with diamond.
    
    
• Loose
  • An unmounted, polished diamond.
    
    
• Lot
  • A group of rough diamonds offered for sale by the Diamond Trading Co. to firms invited to view its "sights." A lot usually includes a wide variety of material.
    
    
• Loupe Clean
  • Describing a flawless gem; no visible inclusions under 10X magnification.
    
    
• Lower Girdle Facet
  • A facet on the pavilion of a round brilliant just below the girdle.
    
    
• Lower-Half Length Percentage
  • Lower-Half Length Percent is the average lower half length relative to the distance between the girdle edge and the center of the culet, listed to the nearest 5 percent [5%].
    
    
• Luminescence
  • Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions, or stress on a crystal.
    
    
• Lustre, Luster
  • Is the degree to which a diamond or gemstone reflects light.
    
    

M


• Macle, Macles
  • A twinned rough diamond crystal, often triangular and flattish. Also spelt maccle, maccles
    
    
• Made
  • Made by humans rather than occurring in nature.
    
    
• Main Facets
  • The first sixteen facets to be ground onto rough diamonds, apart from the table and culet, also the main pavilion facets (the first eight on the pavilion).
    
    
• Make
  • Make of a diamond refers to how well a stone is cut and faceted to bring out the full beauty of the rough crystal. Good proportions, symmetry, and polish effect the beauty of a diamond much more than perfect color or clarity.
    
    
• Marcasite
  • Chemical composition -- Iron sulfide. Often confused with pyrite or fool's gold, a slightly denser form of iron sulfide that crystallizes in the isometric (cubic) system.
    
    
• Marquise Cut
  • The Marquise Cut is a very popular cut which is used to give appropriate and striking shapes to the diamonds. It is mainly employed to produce designer jewelries which have a good market in today's global world.
    
    
• Master, Master Stone
  • Master stones are carefully selected diamonds used by diamond grading laboratories for colour comparison, they are also distributed for use by others who need to grade diamonds accurately.
    
    
• Master Set
  • A set of color comparison diamonds that defines diamond color grades in the normal (D-to-Z) range.
    
    
• Melee
  • Classification used in the sorting of diamonds weighing less than carat.
    
    
• Metal
  • Metals commonly used in the metalsmith's studio can be divided into two groups. Colored metals would include pure gold, most gold alloys, copper, and non-precious alloys such as brass or bronze.
    
    
• Millegrain, Milgrain
  • Literally a thousand grains, setting style where a large number of small grains of metal are raised up to create the diamond setting, a form of rim or bezel setting.
    
    
• Millenium Star
  • The Millennium Star is a famous diamond owned by De Beers. At 203.04 carats (40.608 g), the world's second largest known top-color (D), internally and externally flawless, pear-shaped diamond.
    
    
• Millimeter
  • The millimetre (American spelling: millimeter, symbol mm) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length.
    
    
• Mine Cut Diamond
  • Differs from the modern Brilliant cut only in its girdle shape, which is square instead of round, a higher crown, smaller table, deeper pavilion, and larger culet, but the number and arrangement of the facets are the same.
    
    
• Mixed-Cut
  • A way in which diamonds are cut. Mixed-cut diamonds combine the qualities of the brilliant and step-cuts.
    
    
• Model, Models, Modelling
  • A physical model (most commonly referred to simply as a model, however in this sense it is distinguished from a conceptual model) is a smaller or larger physical copy of an object. The object being modelled may be small (for example, an atom) or large (for example, the Solar System).
    
    
• Modern Brilliant Cut
  • Often known as the brilliant, round, round brilliant, or "brill.". Has 58 facets, including the table and culet.
    
    
• Modified Brilliant Cut
  • The modified brilliant cut is a classification for diamond shapes that include fancy shapes such as the oval, pear, marquise, heart and trillian.
    
    
• Moh's Scale
  • The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
    
    
• Moissanite
  • An extremely rare natural occurring mineral scientifically known as Silicon carbide is a compound made of ceramic components of silicon and carbon that is feigned on a bulk scale for utilizing essentially as an abrasive.
    
    
• Mount
  • The mount in which a gemstone is set in a finger ring, pendant, brooch, etc. The method in which a stone (or stones) is secured in a finger ring, either by a close setting or an open setting, in contrast to the method of incrustation.
    
    
• Mounting
  • Mounting is the process of setting or attaching a gemstone or diamond. It's also a piece of jewelry, into which gemstones or diamonds can be set.
    
    

N


• Nail Head, Nailhead
  • Round brilliant diamond with a dark centre which resembles the head of a nail; caused by a pavilion depth greater than 48 percent.
    
    
• Natural
  • A part of the original natural surface of the diamond crystal left unpolished on the girdle by the cutter striving for maximum weight retention.
    
    
• Natural Gemstone
  • Any gemstone that that occurs in nature and is not created in a laboratory.
    
    
• Needle
  • The crystal or mineral inclusions in the shape of long thin needles are referred as needle flaws. In few cases, these can be of different colour that is clearly visible in the colourless Diamond.
    
    
• Nick
  • Small chip or indentation on the surface of a diamond. Usually found on the girdle.
    
    
• Nick Setting
  • The nick setting is similar to the channel setting. Stones are placed in a row, with metal bordering either side. In a nick setting, small prongs are nicked from the surrounding metal to secure the stones.
    
    
• Nickel
  • A hard, bright, silver-white metallic element of the iron group that is malleable, ductile, and resistant to corrosion.
    
    

O


• Off-center Culet
  • A culet that, due to differences in the angles of the opposite pavilion facets, is off center with respect to the girdle outline.
    
    
• Off-Make
  • A poorly cut or proportioned diamond.
    
    
• Old European Cut
  • A round Brilliant cut with 58 facets, similar to the old mine cut, first appearing in around the 1880's. It is characterized by a deep pavilion, high crown, and an open culet.
    
    
• Old Mine Cut
  • Commonly called Old Miners, the Old Mine Cut has a large culet, a high crown, a small table and is somewhat square, with rounded corners, in outline.
    
    
• Open Culet
  • A term for a culet that is larger than a normal culet.
    
    
• Open Table
  • A term describing a larger than normal table facet.
    
    
• Optical Property
  • A gemstone's ability to interact with light. Some optical properties are color, dispersion and fluorescence.
    
    
• Orlov
  • The Orlov (sometimes spelled Orloff) is a large diamond that is part of the collection of the Diamond Fund of the Moscow Kremlin. The origin of this resplendent relic – described as having the shape and proportions of half a hen's egg – can be traced back to the 18th century Sri Ranganathaswamy Hindu temple, in Srirangam, Tamil Nadu, India where it once served as the eye of the presiding deity.
    
    
• Oval Cut
  • An elliptical shaped diamond or gemstone that is slightly oblong.
    
    

P


• Palladium
  • One of the white metals belonging to the platinum group, palladium is sometimes alloyed with gold. It is less expensive than platinum. It does not tarnish, has good working properties and weighs only a little more than half as much as platinum, making it a favored for use in jewelry.
    
    
• Parcel, Parcels
  • Gems sold as a group.
    
    
• Pavé
  • Pavé is a style of jewelry setting in which numerous small diamonds are mounted close together to create a glistening diamond crust that covers the whole piece of jewelry and obscures the metal under it.
    
    
• Pave
  • Pave is a method of setting diamonds very closely together, giving the illusion of one or more larger diamonds.
    
    
• Pavilion
  • The pavilion is the lower sloping portion of a cut and faceted gemstone.
    
    
• Pavilion Angle
  • The angle measured between the girdle and the pavilion main facet.
    
    
• Pavilion Facet
  • Also often simply called pavilion facets, these are the eight large four-sided facets which run from the bottom point or culet, to the girdle.
    
    
• Perfect
  • Only D colour and flawless diamonds should be described as perfect.
    
    
• Pear Shape Diamond
  • The modified brilliant-cut pear shaped diamond is a combination of a round and a marquise shape, with a tapered point on one end. The diamond is always worn with the narrow end pointing toward the hand of the wearer.
    
    
• Perfect, Perfection
  • Only D colour and flawless diamonds should be described as perfect.
    
    
• Phosphorescence
  • A lingering emission of light following exposure to Ultraviolet light or other energy.
    
    
• Photoluminescence
  • The emission of visible light by a diamond due to the incidence of light of a different wavelength, including fluorescence and phosphorescence.
    
    
• Pick
  • A "pick" is when a buyer is permitted by the seller to select one or more diamonds from a parcel.
    
    
• Picking Price
  • Normally a higher price is charged to a buyer wishing to take one or more selected stones from a parcel, this is known as a picking price.
    
    
• Pink Diamond
  • One of the rarest and most desirable colours for diamond.
    
    
• Pink Gold
  • This gold is a gold and copper alloy widely used for specialized jewelry. It is also known as pink gold and red gold. As it was popular in Russia at the beginning of the nineteenth century, it is also known as Russian gold, however, this term is now archaic. Although the names are often used interchangeably, the difference between red, rose, and pink gold is the copper content – the higher the copper content, the stronger the red coloration. A common alloy for rose gold is 75% gold and 25% copper by mass (18 karat). Since rose gold is an alloy, there is no such thing as "pure rose gold".
    
    
• Pinpoint, Pinpoints
  • Miniscule spots internal to a Diamond. A cluster of pinpoints can form a cloud.
    
    
• Pipe, Pipes
  • The common name for a vertical, columnar mass of rock that cooled and solidified in the neck of a volcano. When these rock masses consist of kimberlite, they often contain diamonds. They occur in Africa, India, Russia, Arkansas and elsewhere.
    
    
• Piqué
  • A diamond so classified for its lack of clarity (or purity) as a result of its having very small inclusions (piqués) of carbonaceous material, usually visible to the naked eye.
    
    
• Pit
  • Tiny holes, often appearing as white dots, on the surface of the diamond. Smaller pits can be polished away, but larger pits on the diamond's table may require re-cutting, causing the diamond to lose weight.
    
    
• Platinum
  • Called the "King of Metals", platinum is a very heavy (nearly twice the weight of gold), silver-white metal that is very ductile. Although it is a soft metal, platinum is not easily scratched and is very strong and durable.
    
    
• Point
  • A weight of one hundredth of a carat, written as 0.01 cts.
    
    
• Polish, Polished, Polishing
  • The reduction of a rough or irregular surface to a smooth flatness or curvature. In diamond fashioning, it is used to include both lapping, or blocking, and brillianteering, as well as the production of any facet; the final operation in fashioning a diamond, usually done with diamond powder on a horizontal disc, or lap, against which the diamond is held in a dop.
    
    
• Polish Lines
  • Tiny parallel lines or surface clouding left by irregular polishing or excessive heating during polishing, respectively.
    
    
• Polish Mark
  • Also known as "Wheel Marks," whitish film on the surface of a facet caused by excessive heat during polishing.
    
    
• Polished Girdle
  • A girdle which had been finely ground to a polished finish instead of the older and simpler matt finish left by bruting.
    
    
• Precious Metals
  • As the name suggest the precious metals and stones are those metals and stones which are rarely found and have more worth in the world market.
    
    
• Princess Cut
  • A more recent adaptation of the barion is the princess cut, which often finds its way into solitaire engagement rings. Flattering to a hand with long fingers, it is often embellished with triangular gems at its sides.
    
    
• Prong Setting
  • The most popular style for engagement rings, prong settings consist of either 4 or 6 metal prongs that are formed around the stone and bent over the top to hold it in place.
    
    
• Proportions
  • Describes the cutting quality relative to the Table Percentage, Depth Percentage, Girdle Percentage, Crown and Pavilion angles and symmetry.
    
    
• Proportionscope
  • Quartz, the most common mineral found on the earth's surface is a component of almost all the types of rock. Quartz has a wide variety with respect to variety, color and forms.
    
    

R


• Radiant
  • The Radiant Cut design was created by Henry Grossbard of the Radiant Cut Diamond Company, not so long ago in 1977. Gemstones have a total of 70 facets, combining the shape of an emerald cut gem and the sparkle of a brilliant cut square or rectangular gem.
    
    
• Rap, Rapaport
  • The Rapaport Diamond Report provides jewelers, diamond dealers and manufacturers with the key information they need to succeed in the diamond industry. Pricing, availability and market information in the magazine provide a critical edge in the complex and competitive diamond, gem and jewelry marketplace.
    
    
• Rapaport Price List
  • The Rapaport Diamond Report provides jewelers, diamond dealers and manufacturers with the key information they need to succeed in the diamond industry. Pricing, availability and market information in the magazine provide a critical edge in the complex and competitive diamond, gem and jewelry marketplace.
    
    
• Rapnet
  • RapNet is the Rapaport Diamond Trading Network connecting thousands of the best diamond suppliers and buyers around the world. It is the primary market for GIA and other certified diamonds.
    
    
• Ratio
  • In mathematics, a ratio is a relationship between two numbers of the same kind (i.e., objects, persons, students, spoonfuls, units of whatever identical dimension), usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second (not necessarily an integer).
    
    
• Ray
  • In optics, a ray is an idealized narrow beam of light.
    
    
• Red Diamond
  • Red diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known.
    
    
• Reflection
  • When a ray of light touches the surface of a diamond, part of the light is reflected back, this is external reflection.
    
    
• Refraction<
  • When a ray of light passes from air into a denser medium, such as a gemstone, part is reflected from the surface and part enters the gem material.
    
    
• Refractive Index
  • The refractive index of a gemstone is an important characteristic which helps to determine the appearance of the gem. This property can easily be measured to help in identifying gemstones.
    
    
• Return of Light
  • When a diamond has a high quality cut (ideal cut), incident light will enter the stone through the table and crown, traveling toward the pavilion where it reflects from one side to the other before bouncing back out of the diamond's table toward the observer's eye. This phenomenon is referred to as "light return" which affects a diamond's brightness, brilliance, and dispersion. Any light-leakage caused by poor symmetry and/or cut proportions (off-make) will adversely affect the quality of light return.
    
    
• Rhodium, Rhodium Plating
  • Rhodium has a lower density and weight than platinum, but it is heavier than gold. Due to its low electrical resistance, rhodium is also used as an electroplate finish on electrical contacts.
    
    
• Ring Setting
  • Whether you're choosing a diamond solitaire or a ring with multiple diamonds, the ring setting is an integral part of the piece's design.
    
    
• Ring Size
  • Manufactured rings are cast to industry standard sizes. Size is unisex and is number based, running in whole as well as half sizes. The "standard" size for women is size 7; for men, size 10.
    
    
• River
  • Riverstones are smooth, rounded pebbles found in rivers and on beaches. They become naturally polished as water and other rocks move against them. Some say they are related to jasper.
    
    
• Round Cut or Brilliant Cut
  • Round brilliant cut gemstones are known to have the most vibrancy and sparkle. With 57 or 58 facets radiating from the center out to the girdle, a brilliant cut maximizes the amount of light that is reflected from the core of the gemstone.
    
    
• Rounding Up or Girdling
  • Rounding up is the process of giving a circular shape to a gemstone. In this process, a gemstone is held in a lathe, or in a cutting machine, and cut or shaped by another diamond or tool, called a sharp.
    
    
• Rolo Chain
  • A rolo chain is made up of symmetrical links (usually round or oval) that are connected together.
    
    
• Rope Chain
  • A rope chain consists of oval links that are linked so that they produce a woven rope arising from the resultant spiral effect.
    
    
• Rose Cut
  • A style of diamond cutting or other transparent gemstone that produces a gem with a flat base and triangular facets that rise to form a dome. This style of cut has been in use since the 16th century.
    
    
• Rough Diamond
  • Diamond as it is first found in the ground, before it has been cut and polished.
    
    
• Rough Girdle
  • A grainy or pitted girdle surface usually caused by poor workmanship.
    
    
• Round Brilliant Cut
  • Round brilliant cut gemstones are known to have the most vibrancy and sparkle. With 57 or 58 facets radiating from the center out to the girdle, a brilliant cut maximizes the amount of light that is reflected from the core of the gemstone.
    
    
• RTZ, R.T.Z., Rio Tinto Zinc
  • Rio Tinto Diamonds operates three diamond mines: the Argyle Diamond Mine in Western Australia (100% ownership), the Diavik Diamond Mine in the Northwest Territories of Canada (60% ownership), and the Murowa Diamond Mine located in Zimbabwe (78% ownership). Together, these three mines produce 20% of the world's annual production of rough diamonds, making Rio Tinto the world's third-largest producer of mined diamonds.
    
    
• Ruby
  • Ruby is the red manifestation of corundum; all other colors of corundum are referred to as sapphire. Due to its durability, brilliance and bewitching red color, it has for thousands of years been considered to be one of the most valuable gemstones.
    
    
• Ruthenium
  • Ruthenium (abbreviated Ruth or Ru) is a precious metal that belongs to the platinum group of metals.
    
    

S


• Safety Clasp
  • A safety clasp is a secure type of closure on a piece of jewelry. The term safety catch is used for a variety of these closures.
    
    
• Sand
  • Sandstone is a common type of grainy sedimentary rock that is made mostly of sand-sized grains (usually quartz) that are held together by silica, calcium carbonate, clay, or iron oxide.
    
    
• Sapphire
  • Sapphires come in all ranges of colors from blue to black to colorless and all colors in between. There are no limits to the color tone or saturation of color in a sapphire.
    
    
• Satin Finish
  • Satin finish, also known as a brushed or matte finish, is a texturing technique used on jewelry metals where a series of tiny parallel lines are scratched on the surface with a wire brush.
    
    
• Saturation
  • Saturation is one of three characteristics used to describe the appearance of color. Saturation (also known as intensity) refers to the brightness or vividness of a color.
    
    
• Scaife
  • Diamond polishing tool.
    
    
• Scintillation
  • Scintillation (sparkle) is the tiny flashes of light noticeable in a diamond when the observer moves his/her head.
    
    
• Scratch
  • A linear indentation normally seen as a fine white line, curved or straight.
    
    
• Screw Back
  • A screw back is an ear nut that screws onto a threaded earring post; usually used with diamond stud earrings.
    
    
• Scratches
  • These are referred to as thin lines on the surface. It is mostly formed when the stone undergoes the different steps of gemstone processing like cutting or polishing. There are very less chances that it happens naturally.
    
    
• Semi-Mount
  • A semi-mount is a jewelry setting that has already been partially finished with accent gems and/or diamonds with the exception of the center stone.
    
    
• Semi Precious, Semi-Precious
  • A gemstone or gem (also called a precious or semi-precious stone, or jewel) is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. The traditional classification in the West, which goes back to the Ancient Greeks, begins with a distinction between precious and semi-precious stones; similar distinctions are made in other cultures. In modern usage the precious stones are diamond, ruby, sapphire and emerald, with all other gemstones being semi-precious.
    
    
• Setter
  • Craftsman setting a gem stone into a setting.
    
    
• Setting
  • Setting refers to the style in which a gemstone is held by precious metal into a mounting. Common settings include bezel, pave', channel or prong. Setting also refers to the part of jewelry in which one or more stones are set.
    
    
• Shallow Cut
  • When the cut of a diamond is too shallow, light escapes through the pavilion before it can be reflected.
    
    
• Shank
  • The part of a ring that encircles the finger.
    
    
• Shape
  • Diamonds are natural crystals that come in large variety of shapes such as round, princess, heart, oval, marquise etc. The following information will help you to choose the right shaped diamond.
    
    
• SI or Slightly Included
  • Diamond clarity grading scale. Slightly Included category (SI) diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification. The SI category is divided into two grades; SI1 denotes a higher clarity grade than SI2. These may or may not be noticeable to the naked eye.
    
    
• SI3
  • The SI3 was born out of the desire of the Diamond Industry to incorporate an extra grade to identify Diamonds in the lower range of the clarity scale. Many complained that there is too wide a gap between the SI2 and the I1 grade.
    The problem with the SI3 today is that GIA, the largest and most widely accepted Gem Laboratory in the world, does not recognize SI3 grades.
    Some say the SI3 is a good idea, some say it is a bad idea. We feel that it can be a good idea if implemented properly.
    If taken to an appraiser, our SI3 diamonds will be graded as SI3 by an EGL gemologist and as either SI2 or I1 by a GIA gemologist. Our SI3 diamonds usually appraise as SI2 with GIA we can not guarantee they will not be appraised as I1, so please keep this in mind when purchasing your diamond. If you are not satisfied with the quality of your SI3 diamond for any reason, you may upgrade it for the difference in prices between the two diamonds at no additional labor and setting costs to you.
    
    
• Sidestone
  • Diamonds setted around the center stone.
    
    
• Sierra Leone
  • Officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of 71,740 km2 (27,699 sq mi) and has a population of 6.4 million. It was a colony under the auspices of the Sierra Leone Company from March 11, 1792 until it became a British colony in 1808. Sierra Leone has a tropical climate, with a diverse environment ranging from savannah to rainforests. Freetown is the capital, largest city and economic and financial center. The other major cities are Bo, Kenema, Koidu Town and Makeni.
    
    Annual production of Sierra Leone's diamond estimates range between $250–300 million US$. Some of that is smuggled, where it is possibly used for money laundering or financing illicit activities. Formal exports have dramatically improved since the civil war with efforts to improve the management of them having some success. In October 2000, a UN-approved certification system for exporting diamonds from the country was put in place and led to a dramatic increase in legal exports. In 2001, the government created a mining community development fund (DACDF), which returns a portion of diamond export taxes to diamond mining communities. The fund was created to raise local communities' stake in the legal diamond trade.
    Sierra Leone is also known for its blood diamonds that were mined and sold to diamond conglomerates during the civil war, in order to buy the weapons that fuelled the atrocities of the civil war. In the 1970s and early 1980s, economic growth rate slowed because of a decline in the mining sector and increasing corruption among government officials.
    
    
• Sieve
  • Sieving is a simple and convenient technique of separating particles of different sizes. A small sieve such as that used for sifting flour has very small holes which allow only very fine flour particles to pass through. The coarse particles are retained in the sieve or are broken up by grinding against the screen windows. Depending upon the types of particles to be separated, sieves with different types of holes are used. Separating tea leaves from tea is not considered to be sieving.
    
    
• Sight, Sights
  • Being a sightholder has always been considered a status symbol; reaching the pinnacle of one's professional career. Before the Supplier of Choice program, criteria for becoming a sightholder were fairly standard - well established, diamond expertise, substantial capital, manufacturing capabilities, and potential to finance work in progress for several months.
    
    
• Sightholder, Sight-holder
  • A sightholder is a company on the Diamond Trading Company's (DTC) list of authorized bulk purchasers of rough diamonds. DTC is controlled by the De Beers Group, the single largest producer and purveyor of rough diamonds in the world. In May 2006, DTC released a list of the 93 sightholders on its website.
    The DTC Sightholder list was further reduced to 79 companies worldwide in December 2007. The list of selected companies for the 2008-2011 contract period was published in April 2008.
    
    
• Silver, Sterling
  • Silver is a metallic chemical element with the chemical symbol Ag (Latin: argentum, from the Indo-European root *arg- for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.
    
    
• Silver Cape
  • Silver Cape is a type of diamond color taken from the old English method for defining diamond colors, which is disappearing today. Silver Cape diamonds are light yellow, equivalent to L, K ranking, according to color parameters set by the Gemological Institute of America (GIA). Generally, the English method defines a diamond's colors according to the mines in which it was found. The name Silver Cape, based on this method, is derived from the "Cape" mines in South Africa which yield yellowish diamonds.
    
    
• Silver Wedding
  • 25th wedding anniversary.
    
    
• Single Cut
  • Invented in the late 14th century, the "old single cut" (aka "old eight cut") diamond has the addition of corner facets to create an octagonal girdle, an octagonal table, eight bezel or crown facets, and eight pavilion facets.
    
    
• Single Refraction
  • Single Refraction - Light that passes through a crystal without being resolved into two rays. They are also called Isotropic because light passes through them with the same velocity in all directions.
    
    
• Simulate, Simulated, Simulant
  • The IDC defines a simulated diamond or a diamond simulant as product that has the intention of imitating a diamond. The IDC actually does not allow companies to use the word diamond in combination with simulant, though many companies do.
    
    
• Slightly Yellow<
  • A diamond color grade that is used by some dealers for a stone showing an obvious yellow tint to the unaided eye.
    
    
• Snake Chain
  • Like the omega chain, the snake chain (also known as Brazilian chain) is also not made up of traditional linked rings. It is instead of made up of round wavy smooth metal plates joined so that it forms a flexible tube.
    
    
• Snap-Lock Clasp
  • A type or closure for an earring which lifts up and down in order to secure or release the earring.
    
    
• SOC, S.O.C.
  • Supplier of Choice. The Diamond Trading Company's (DTC) sales strategy is known as 'Supplier of Choice' (SoC) and was implemented in 2003. It sought to build a more efficient channel for rough diamond distribution by the DTC and maintain ethical transparency amongst the DTC's client base. SoC aims to place all De Beers diamonds into the hands of exceptionally able diamond businesses best equipped to add long term, sustainable value to them.
    
    
• Solder
  • A technique used in making and repairing jewelry whereby two pieces of metal are joined by applying a molten metal which has a lower melting point than the two metals being joined.
    
    
• Solitaire
  • Solitaire is a piece of jewelry that features a solo stone. Most commonly refers to a ring set with a diamond. It is also the most popular style of engagement ring.
    
    
• Sort
  • Sorting is any process of arranging items in some sequence and/or in different sets, and accordingly, it has two common, yet distinct meanings. Ordering: arranging items of the same kind, class, nature, etc. in some ordered sequence. Categorizing: grouping and labeling items with similar properties together (by sorts).
    
    
• Sparkle
  • The fire and brilliance created by light passing through a diamond.
    
    
• Spots
  • An inaccurate term used by some people in the jewelry industry to describe the appearance of certain inclusions in a diamond.
    
    
• Spread Stone
  • A diamond that comes with a large table and thin crown height.
    
    
• Spring Ring Clasp
  • A spring ring clasp is a type of clasp made in the shape of a ring. A segment of the ring can be withdrawn into the ring to allow connecting the clasp to a loop.
    
    
• Stainless Steel
  • Stainless steels are a family of steels that are resistant to corrosion (rusting) and elevated temperature. They must contain at least 10.5 % chromium.
    
    
• Star
  • Effect caused by light reflecting off inclusions inside a diamond.
    
    
• Star Facet
  • The eight triangular facets that surround the table facet of a round, brilliant-cut diamond.
    
    
• Square Emerald Cut
  • A form of step cutting with a square girdle outline but modified by corner facets.
    
    
• Step-Cut
  • A way in which diamonds are cut. Step-cut diamonds feature rows of facets positioned in a step-like fashion. Most step-cut diamonds have four sides and a rectangular shape, such as emerald or baguette diamonds.
    
    
• Stud Earrings
  • Stud earrings, also called studs, are a small, simple style of earring for pierced ears. Studs contain a single stone (such as a pearl, gemstone or diamond) or metal ball on a straight post.
    
    
• Supplier of Choice
  • Supplier of Choice. The Diamond Trading Company's (DTC) sales strategy is known as 'Supplier of Choice' (SoC) and was implemented in 2003. It sought to build a more efficient channel for rough diamond distribution by the DTC and maintain ethical transparency amongst the DTC's client base. SoC aims to place all De Beers diamonds into the hands of exceptionally able diamond businesses best equipped to add long term, sustainable value to them.
    
    
• Surface
  • Whether a polished diamond has a good surface, free of blemishes, is a quality factor.
    
    
• Surface Graining
  • Often appearing as parallel lines on the diamond's surface.Similar to polishing lines, and may be the result of irregularities in the diamond's crystal growth.
    
    
• Surface Markings
  • Imperfections on the diamonds's surface. Often described as spots, blisters, or indentations.
    
    
• Swiss Cut
  • Halfway between a brilliant and an eight cut, with 34 facets in total.
    
    
• Symmetry
  • Symmetry refers to how well the diamonds facets are aligned and "pointed". GIA defines symmetry as "the exactness of shape and placement of facets".
    
    
• Synthetic Diamond
  • Synthetic diamond is also known as cultured diamond or artificial diamond. This man-made created stone possess almost same physical and chemical properties as that of real diamonds.
    
    

T


• Table
  • The largest and most important facet on a round brilliant cut diamond is the table. This is the topmost facet. It is, or should be, a symmetrical octagon.
    
    
• Table Cut
  • A simple, obsolete cut with one "slice" cleaved or polished from (usually) an octahedral. forming a table as on a modern stone.
    
    
• Table Percentage
  • The table percentage of a diamond represents the ratio of table width to overall stone width. Like depth percentage, the luster of the stone is directly affected by its table percentage.
    
    
• Table Size
  • Table Size: is calculated as a percentage of the gemstone's total width. The table is described as small if its size is under 33%; acceptable if it is 33-67%; and large if it is above 67%.
    
    
• Tang
  • Most commonly used tool in the diamond polishing process.
    
    
• Tension Setting
  • A method of setting diamonds and other gems using only the springiness of the mount to hold the stone firm. Can look quite spectacular but rather chunky and heavy; insecure otherwise.
    
    
• Tetrahedron
  • Numerous mineral structures are based on the fact that tetrahedra can be inscribed in a cube. If atoms have a face-centered arrangement, we can join a corner atom to the three nearest face-centered atoms to create a tetrahedron. Diamond is one mineral that employs this structure. There are carbon atoms in a face-centered array (dark gray) plus an extra one (light gray) at the center of each tetrahedron.
    
    
• Thermoluminescence
  • Diamond having a nitrogen content not exceeding 100 ppm and electrons or holes trapped at lattice imperfections within the crystal structure has been found to be a good thermoluminescent material. The diamond is produced by taking a diamond having a nitrogen content not exceeding 100 ppm and subjecting it to nuclear radiation.
    
    
• Thickness
  • Usually describing a girdle, and often expressed as a percentage of the height or depth of the diamond, often using relative terms such as "medium".
    
    
• Tiffany
  • 128.51 carats, found in the Kimberly mine of South Africa, in 1878. It weighed 287.42 carats as a rough diamond. It was bought by the jewelers Tiffany in New York and cut in Paris with 90 facets.
    
    
• Titanium
  • Titanium is a light, strong, lustrous metal. Pure titanium is as strong as steel and can withstand a lifetime of punishment.
    
    
• Toggle Clasp
  • Toggle clasps are used to secure the ends of bracelets, necklaces and chains. They are made with a bar that slips through a round, square or triangle shape.
    
    
• Tolkowsky Cut
  • In 1919, Marcel Tolkowsky, a member of a Belgian family of diamond cutters, published Diamond Design, the first recorded analysis of diamond proportions for the round brilliant cut diamond. His work was based on modern theories of light behavior and his opinion of what proportions resulted in what many industry professionals considered to be the best possible balance of brilliance and dispersion of light until the late 1990's.
    
    Tolkowsky's calculations indicate that for optimum brilliance a round brilliant cut diamond should be cut to the following angles and proportions: 34.5° Crown Angle, 40.75° Pavilion Angles, 59.3% Total Depth (excluding girdle thickness) with 16.2% of the depth being comprised of the crown (top half of the diamond) and 43.1% representing the pavilion lower half of the diamond, 53% Table based on diamond's overall diameter.
    
    
• Tone
  • Tone is one of the characteristics used to describe the appearance of color. Tone refers to the lightness or darkness of a particular stone.
    
    
• Tongue Clasp
  • A clasp in which a V-shaped wire fits into a small tube and locks into place. On broader necklaces, the snap is square.
    
    
• Total Depth Percentage
  • The Total Depth Percentage is the depth of a diamond, from the table to the culet, divided by the average diameter or width of the girdle. The depth of most diamonds is between 53 and 63 percent.
    
    
• Top Light Brown
  • Most diamonds seen in High Street shops are slightly yellow or brown. This page is about "light brown" and "top light brown" diamonds.
    
    
• Top Silver Cape
  • Silver Cape is a type of diamond color taken from the old English method for defining diamond colors, which is disappearing today. Silver Cape diamonds are light yellow, equivalent to L, K ranking, according to color parameters set by the Gemological Institute of America (GIA). Generally, the English method defines a diamond's colors according to the mines in which it was found. The name Silver Cape, based on this method, is derived from the "Cape" mines in South Africa which yield yellowish diamonds.
    
    
• Top Wesselton
  • Top Wesselton refers to colors F and G, some may also call color F a Top Wesselton+ .
    
    
• Total Internal Reflection
  • Total internal reflection ian optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary, no light can pass through and all of the light is reflected. The critical angle is the angle of incidence above which the total internal reflection occurs.
    
    
• Toughness
  • Toughness relates to a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 3.4 MN m-3/2,[8] which is good compared to other gemstones, but poor compared to most engineering materials.
    
    
• Transparent, Transparency
  • Transparency: refers to a gemstone's relative ability to transmit light.
    
    
• Trap Cut
  • Stones whose outlines are either square or rectangular and whose facets are rectilinear and arranged parallel to the girdle are known as step- or trap-cut stones. These stones often have their corners truncated, creating an emerald cut (after its most common application to emerald gemstones) with an octagonal outline. This is done because sharp corners are points of weakness where a diamond may cleave or fracture. Instead of a culet, step-cut stones have a keel running the length of the pavilion terminus. Because both the pavilion and crown are comparatively shallow, step cut stones are generally not as bright and never as fiery as brilliant cut stones, but rather accentuate a diamond's clarity (as even the slightest flaw would be highly visible), whiteness, and lustre (and therefore good polish).
    
    
• Treatment
  • Artificial modification of the chemical and/or physical properties of a gemological material. In pearls, any operation for changing and improving their aspect.
    
    
• Trigon, Trigons
  • A triangular indentation occurring as a growth mark on diamond octahedron faces. The sides of the trigon are reversed with respect to the face on which it occurs.
    
    
• Trillion or Trilliant Cut
  • Trillion cut is a triangular shaped diamond with truncated corners and 44 varying facets.
    
    
• Troy Weight
  • The measure used to weigh Gold, Silver and jewels. In Troy weight, the pound = 12 ounces, the ounce = 20 pennyweights, and the pennyweight = 24 grains.
    
    
• Tungsten
  • Tungsten also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74.
    
    A steel-gray metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the non-alloyed metals and the second highest of all the elements after carbon. Also remarkable is its high density of 19.3 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead. Tungsten with minor amounts of impurities is often brittle[4] and hard, making it difficult to work. However, very pure tungsten is more ductile, and can be cut with a hacksaw.
    
    
• Twinning Lines
  • Visible line on or with in a fashioned diamond, caused by twinning in the crystal.
    
    
• Twinning Wisp
  • Twinning Wisp inclusions are naturally-occurring structural defects with a diamond, resulting from crystal twining during the growth process.
    
    

U


• Ultrasonic Cleaner
  • A machine that cleans jewelry by using a fluid that is vibrated at 20,000 cycles per second.
    
    
• Ultraviolet, UV, U.V.
  • Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV. It is named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet. Although ultraviolet is invisible to the human eye, most people are aware of the effects of UV through the painful condition of sunburn, but the UV spectrum has many other effects, both beneficial and damaging, to human health.
    
    
• Unmounted
  • Diamond that has been removed from setting/mount.
    
    
• Unpolished
  • Raw diamond before polishing.
    
    
• Upper Girdle Facet
  • An upper girdle facet is one of the 16 facets found on the lower crown portion of the diamond (abutting the girdle).
    
    

W


• Wedding Ring
  • A wedding ring or wedding band is a metal ring indicating the wearer is married. Depending on the local culture, it is worn on the base of the right or the left ring finger. The custom of wearing such a ring has spread widely beyond its origin in Europe. Originally worn by wives only, wedding rings became customary for both husbands and wives during the 20th century.
    
    
• Weight Ratio
  • A comparison of a diamond's weight in relation to its diameter.
    
    
• Wesselton
  • The name Wesselton is now given to clean, well-made cut diamonds, with a quality rating between top crystal and Jagers.
    
    
• White Gold
  • White gold is an alloy of gold and nickel, sliver, or palladium. The inclusion of white metals in the alloy give white gold its silvery color.
    
    
• White Light
  • White light is the effect of combining the visible colors of light in suitable proportions (the same present in solar light).
    
    
• Wisp
  • Twinning Wisp inclusions are naturally-occurring structural defects with a diamond, resulting from crystal twining during the growth process.
    
    
• World Diamond Council, WDC, W.D.C.
  • The World Diamond Council (also known during its prototype period as the International Diamond Council) is an organization consisting of representatives from diamond manufacturing and diamond trading companies. The Council was set up in July 2000 to examine ways to reduce the number of conflict diamonds entering the diamond market.
    
    

X


• Xenon
  • Xenon is a chemical element with the symbol Xe and atomic number 54. A colorless, heavy, odorless noble gas, xenon occurs in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.
    
    
• X-Ray, Xray, Xrays, X-Rays
  • X-rays can penetrate solid objects, and their most common use is to take images of the inside of objects in diagnostic radiography and crystallography. As a result, the term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. By contrast, soft X-rays hardly penetrate matter at all; the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometer.
    
    

Y


• YAG, Y.A.G.
  • Yttrium aluminium garnet is a synthetic crystalline material of the garnet group. It is also one of three phases of the yttria-aluminium composite, the other two being yttrium aluminium monoclinic (YAM) and yttrium aluminium perovskite (YAP). YAG is commonly used as a host material in various solid-state lasers.
    
    
• Yellow Gold
  • Even though gold is yellow when pure, the intensity of yellow color depends on volume of other metals alloyed with it. The more the karat weight, more intense is the color. The most popular gold alloy made up of gold, silver, copper, and often zinc.
    
    
• Yellow Ground
  • Weathered kimberlite which is colored yellow.
    
    

Z


• Zircon
  • Zircon is a natural crystalline gemstone, which is older than diamond and is available in a pallet of colors. It is a very primitive stone whose age is approximately 4.404 billion years.
    
    
• Zirconia
  • The diamond substitute known as cubic zirconia was found naturally formed in the 1930's but today it is simulated in a laboratory environment, as natural forms are no longer easily found.