A

AGS:   Abbreviation for "American Gem Society"

African emerald:   A term commonly used to describe green fluorite that is mined in South Africa. A gemstone referred to as an African emerald is usually not a natural emerald.

Agate:   A gemstone that is a striped version of chalecedony quartz, agate forms in layers in many colors and textures by filling-in an indentation or cavity in another rock.   When agate is sliced, its concentric layers become obvious, sometimes appearing as bands that resemble the growth rings of a tree trunk. The bands can be different colors, widths and textures. Some even look like a bed of moss or a forest scene.

Alexandrite:   A transparent variety of the mineral chrysoberyl that is green by daylight and red (preferably) to almost violet in incandescent artificial light.

Alloy:   A compound metal resulting from melting two or more metals together. Sterling silver, for example, is composed of 92.5% pure silver and 7.5% pure copper.

Alternative: The choice between two mutually exclusive possibilities.

Amethyst:   A transparent, pale-violet to deep-purple variety of crystalline quartz. Major sources:   Siberia, Brazil, Uruguay.

Aquamarine:   The transparent, very light to medium-dark blue to greenish-blue variety of beryl.

Asscher cut:   A diamond cut named for its inventor, Joseph Asscher, who in 1902 developed a square cut diamond with 74 facets. The cut's wide step facets and deep clipped corners make the gemstone resemble an octagon.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Assembled stone:   Any stone constructed of two or more parts of gem materials.

B

Baguette:   From the French, meaning rod. A style of step cutting for small, rectangular shaped gemstones.

Baroque:   Relating to the decorated style of buildings, art, and music that was popular in Europe in the 17 th century and the early part of the 18 th century.

Bead setting:   A setting in which the prongs are formed (raised) by an engraving tool to secure the stone in a setting. These prongs are then rounded and pushed over the edge of a stone with a beading tool.

Bearded girdle:   If a gemstone is rounded up carelessly in the fashioning (polishing) process the surface of the girdle will turn out rough and numerous minute hair-like fractures are likely to extend a short distance into the stone. A girdle with this appearance is referred to as being bearded. A gemstone is also referred to a bearded if it has small chips and abrasions (usually from hard wear) on its girdle.

Beryl:   A mineral species that includes the gem varieties emerald, aquamarine, and morganite.

Bezel setting:   A style of setting which encloses the girdle of a stone. A stone is placed into a tube, the top of which is then hammered over the girdle completely encircling and securing it.

Black diamond:   When a diamond is dark gray, a very dark green or truly black, it is referred to as a black diamond. Such a stone may be opaque to nearly semitransparent.

Blemish:   Any surface imperfection on a cut diamond. Such as a nick, knot, scratch, abrasion, minor crack or cavity.

Blood diamonds:   Diamonds that help arm terrorists, according to United Nation reports.   African children were brutally maimed by thugs who funded themselves with uncut diamonds.   Senator Dick Durbin said, "The diamond-a symbol of love in America-should not be paid for by the blood of Africans.The brutal wars in African Nations may be thousands of miles away, but the source of the funds that buy the weapons may be a close as your ring finger."

Blue ground:   Unoxidized rock in diamond pipes.

Blue-white:   A term that has been used to refer to a diamond without body color. Unfortunately it is applied frequently to diamonds that have a distinct yellow tint. Flagrant misuse has made the term totally meaningless. The term is rarely used today, and if, it is usually for deceptive purposes to imply a better color.

Body color:   The color of a gemstone 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 influence the color determination.

Bort:   Diamonds fit for industrial/mechanical purposes only.

Bourse:   French, meaning an exchange or meeting place where merchants transact business. The word is often used for a diamond dealers club or organization.

Brilliancy:   The total amount of light reflected from both the interior and exterior surfaces of a gemstone. The amount of brilliancy also depends on the cutting, transparency, facet angles, proportions and polish.

Brilliant-cut (round):   The most common style of cutting for diamonds and other stones. The standard round brilliant consists of a total of 58 facets:   1 table, 8 bezel facets, 8 star facets and 16 upper-girdle facets and usually a culet on the pavilion. Modifications of the brilliant style of cutting include such fancy shapes as the marquise, oval, pear shape and many others.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Brutting:   The process of applying the girdle to a cut gem.

Bywater:   Decidedly yellowish diamond.

C

Cabochon stones:   These stones are smooth, convex forms, usually with flat undersides.   They may be round, oval, square or any other shape when viewed from the top, but from the side they take the shape of a rounded mound.   Some translucent stones are cut as cabochons, but most stones cut this way are opaque.   The name is typically shortened to cab.

Canary diamond:   An intensely colored yellow diamond. The yellow must be vivid and deep enough to be an asset. Such a diamond is called a fancy.

Cape:   A broad range of diamond color grades for stones that show a distinct yellow tint.  The term originally referred to the Cape of Good Hope, South Africa. Since the average color produced by the South African mines was distinctly more yellow than the Brazilian average, the term cape became accepted for strongly yellow-tinted stones.

Carat:   A unit of weight for diamonds and other gems. The metric carat of 0.200 grams, or 200 milligrams, was adopted in the United States in 1913 and is now standardized in the principal countries of the world. Not to be confused with karat. Karat refers only to the fineness of pure gold and gold alloys.

Carbon:   An inclusion in a diamond that appears black to the unaided eye. Usually carbon (graphite) or small particles of another mineral. Some inclusions that appear black are actually reflections caused by cleavages (small cracks) or included transparent crystals.

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. After passing an extensive test he is awarded this title.

Champagne diamond:   A greenish-yellow diamond of sufficiently pronounced color to be a positive asset. Also called a fancy.

Channel setting:   Stones set between two ridges of metal with their edges almost touching, usually in a straight line. The sides of the mounting are hammered over to grip the outer edges (girdles) of the stone.

Chip:    A small rose-cut or single-cut gem. Also a break (chip) on a gemstone that extends from a surface edge.

Chrysoberyl:   A very hard and important gem species, of which cat's-eye, alexandrite, and green, brown and yellow chrysoberyl are varieties. Sources:   Ceylon, Russia, Brazil and China.

Citrine:   The transparent yellowish to red-orange to red-brown variety of crystalline quartz. Citrine is often incorrectly referred to as topaz. Major sources:   Brazil, Madagascar and Spain.

Clarity:   The structural quality of a gem.

Clarity grade:   The relative position of a diamond on a flawless-to-imperfect scale. The most common today is the scale used by the GIA.

Clean:   A term used by some jewelers to indicate the absence of imperfections in a diamond. It is often misused to describe diamonds with slight imperfections.

Cleavage:   A term to describe a break within a diamond. Usually the cleavage crack extends to the surface. It is the most damaging kind of imperfection in a diamond, since it affects durability as well as beauty. Also a term sometimes used for a diamond crystal that requires cleavage (splitting) before being cut and polished.

Cloud:   A group of tiny white inclusions in a diamond that together give a cottony or clouded appearance. A cloud is sometimes large enough to deprive the entire stone of brilliancy.

Cluster setting:   Stones set in a group to give the illusion of one larger stone and held by beaded prongs. Usually round clusters consist of six stones arranged around a single center stone.

Coated diamond:   (Also- painted diamond ) A diamond that has been coated with a substance that imparts a bluish color to mask a yellowish body color. Painting diamonds is a deceptive practice.

Cocktail ring:   A fancy design ladies ring using small diamonds and often small colored stones.

Colored diamond:   Referred to as "fancy diamonds" they occur in yellow, brown, pink, red, blue and green.

Color grade:   The relative position of a diamond's body color on a colorless (starting with D) to yellow (Z) scale.

Colorimeter:   An instrument for measuring color. It uses a selenium cell that can measure the relative transmission of yellow and blue light by a diamond.

Colorless diamond:   A diamond totally devoid of any body color.

Commercially clean or commercially perfect:   The common meaning of this term is "reasonably free from inclusions" implying that the diamond is "almost perfect."  Sometimes heavily flawed diamonds are represented in an obvious attempt to mislead as "commercially clean."

Commercial white:   A misleading term that is used to mean not white, but slightly off color.

Conflict Diamonds:   (see Blood Diamonds )

Crown:   Referring to the portion of a faceted gemstone above the girdle.

Culet:   The small facet that is polished parallel to the table across what would otherwise be the sharp point which terminates the pavilion (bottom) of a gemstone. Its function is to reduce the possibility of damage to the stone.

Cultured:   Produced under artificial and controlled conditions.

Cushion cut:   Much like the old-mine-cut, an older form of the brilliant cut, having a girdle outline approaching a square with rounded corners.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Cut:   Shape and quality of the cutting of a gemstone.

Cyclotron-treated-diamond:   A diamond whose color has been changed as a result of bombardment with alpha, neutron, or deuteron particles in a cyclotron particle accelerator.

D

Dark-field illumination:   A method of illuminating gemstones with a strong light from the side while the stone is being viewed against a black background. It causes some inclusions and imperfections to stand out clearly.

De Beers:   The company set up originally by Cecil Rhodes to control the diamond production of South Africa and to exclusively sell these diamonds to the Syndicate in London.   In 2003 it is a private corporation, 45% owned by a Liberian-registered Oppenheimer family company, 45% owned by Anglo American plc (a company in which the Oppenheimers also play a commanding role) and 10% by the Debswana Diamond Company (Pty.), a company owned in equal shares by the government of the Republic of Botswana and De Beers Centenary AG.

Depth percentage:   The depth of a polished gemstone measured from the table (top) to the culet (bottom), expressed as a percentage of the stone's diameter at the girdle, an important factor in grading proportions.

DIAMANG:   Companhia de Diamantes de Angola, a company set up to exploit the diamond resources of Angola.

Diamantaire:   Anyone professionally involved with diamond manufacturing or marketing.

Diamond:   A mineral composed of carbon crystallized into a cubic crystal system by intense heat and pressure. It is the hardest of all natural substances (10 on Moh's scale). It ranges in color from colorless to yellow, brown, orange, green, blue, and violet. Reddish stones are extremely valuable.

Diamond alternative:   Man made, synthetic, or diamond simulant stones made in laboratory settings to emulate the aesthetics of natural diamonds.   These stones are manufactured to be significantly less expensive, and are an ethical alternative for consumers who take issue with and want to remove blood/child labor natural diamond risk.

Diamond cartel:   The corporate mechanism by which De Beers controls the marketing and pricing of most of the world's rough diamonds.   (Also see syndicate )

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.

Diamond Corporation:   A De Beers-owned company, set up to purchase the production of non-De Beers-owned diamond mining companies.

Diamond Trading Company:   A De Beers-owned company (DTC) that sells rough diamonds to diamond merchants.

Diffusion:   Diffusion is the process of applying a temporary coating onto the surface of a gemstone in order to enhance its color.

Dispersion:   The breakup of a light ray into colors of the spectrum.

Dop:   Device for holding diamond during the process of cutting and polishing.

Doublet:   A "gemstone sandwich' made in layered sections. The lower, larger portion is made from glass or an inexpensive stone and has a smaller layer of a more valuable stone adhered to the top of it. Opal doublets are common.

E

Electron-bombarded diamond:   A diamond whose color has been changed to blue by bombarding it with electrons in a Van de Graff generator. Gamma-ray radiation has also been used to produce blue colors.

Emerald:   Medium-light to dark green tones of beryl. There is no standard dividing line between emerald and either aquamarine or the lighter green variety known as green beryl.

Emerald triplet:   An assembled stone. Two parts, the top and the bottom  are either quartz, pale beryl or synthetic spinel and the third part usually is a layer of green cement, serving a colorant while gluing the top to the bottom. The best way to detect these stones are by observing the side while immersed in a clear liquid.

Emerald cut:   A form of "step cutting". Usually rectangular, it has rows (steps) of elongated facets on the crown and pavilion, parallel to the girdle. It also has very pronounced corner facets.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Engagement ring:   A ring given as token of betrothal, especially a solitaire.

Engraving:   A hand-crafted or machined process that removes metal from jewelry in order to create words or decorative motifs. The tool used is called a graver.

Eternity ring:   The diamond eternity ring is a circlet of small gemstones set in gold or platinum.  This type of ring has been used in Europe for hundreds of years as the traditional symbol of eternity.

European cut:   Obsolete brilliant diamond cut, characterized by a very small table, a heavy crown, and great overall depth. Not to be confused with old-mine cut.

Extra facets:   Facets in excess of those needed to achieve a given style of cutting.

Eye clean:   A term that implies that no internal flaws are visible to the unaided eye of a qualified Gemologist.

F

Facet:   A plane (flat) polished surface on a gemstone.

Faceted stones:   A facet, or face, is a small flat plane cut on a stone.   Facets are arranged geometrically over the entire surface of a transparent or translucent gem to focus light into the stone and reflect it back.   All of this enhances the natural sparkle of the stone, which can be round, oval or any of dozens of other shapes.

Fancy colors:   Naturally colored diamonds, excluding many less intense browns since there are too many of them on the market to excite a high price.

Fancy cut:   Any style of gemstone cutting other than the round brilliant cut. Fancy cuts include the marquise, emerald, heart, pear, and other shapes.

Fancy diamond:   Any diamond with a natural body color strong enough to be attractive, rather than just off color.   Red, blue and green are very rare; orange and violet, rare; strong yellow, yellowish-green, brown and black stones are more common.

Faux:   Being an imitation of a genuine article.

Feather:   When the plane of cleaving or fracture in a diamond is viewed at right angles to it, the appearance is often reminiscent of a feather. Thus, cleavage and fracture cracks in diamonds are often called feathers.

Findings:   Findings are the components that jewelry makers use to assemble their jewelry and include items such as clasps, earring backs, and hooks.

Finish:   The quality of a gemstone's polish, smoothness, symmetry and size of the culet.

Fire:   Flashes of the different spectrum colors from dispersion.

Fisheye:   A gemstone whose pavilion (bottom) is exceedingly shallow, producing a glassy appearance and a noticeable lack of brilliancy.

Flaw:   Any external or internal imperfection on or in a polished gemstone; feather, fissure, carbon spot, knot, natural, cleavage, chip, inclusions, etc. The term flaw and imperfection are usually used interchangeably.

Flawless:   A diamond without any blemishes or imperfections as seen under 10 times magnification.

Fluorescence:   Under different rays, ultraviolet, cathode, or x-ray some diamonds fluoresces different colors.

Four C's:   A phrase coined for marketing purposes that sums up the numerous factors affecting diamond value into four categories:   color, clarity, cutting and carat weight.

Fracture Filling:   Fracture filling is a treatment used to fill-in tiny cracks in a gemstone with a clear, glasslike substance. The cracks don't disappear, but the film creates an optical illusion that makes them invisible to the naked eye.

G

Garnet:   Dark red gemstone.

Gem:   A cut-and-polished stone of beauty to be used in jewelry. Also used as a prefix for exceptional quality.

Gemologist:   A specialist in gem materials. One who has successfully completed the study of gem identification, grading, and pricing.

Girdle:   The outer edge, the perimeter or dividing line between crown and pavilion on a cut and polished stone.

Glets (or gletz):   A word of Dutch origin for a  cleavage crack in a diamond that looks like a feather.

Gold:   A yellow-colored metallic element and precious metal, used for coins and jewelry for thousands of years. It is impervious to corrosion and oxidation. It is the most ductile and malleable of all metals.

Gold Filled:   An item with a sheet of gold applied to its surface. Newer items contain markings that indicate how much and what type of gold was used in the layer. A marking of 1/20 12K G.F. means that the piece is at least 1/20th 12K gold by weight.

Gold Plated:   A metal item that has a very thin layer of gold applied to it.

Grain:   The cleavage direction.

Grain mark:   Line on the facet surface due to imperfect polishing.

Grainer:   Diamonds with weights near multiples of one-quarter carat, or one grain are referred to as grainers; e. g. four-grainer for a one carat stone (be careful, this is an approximate, a four-grainer can be smaller than a one carat).

H

Heat treatment:   Heating a diamond or other gem material at a given temperature for a specified period to permit a partial or complete readjustment of the atomic structure that was previously altered by some type of treatment. For example, an irradiated diamond that has turned green may be changed to other colors by heat treatment.

I

I: Imperfect.   A stone in which a flaw can easily be seen.

Ideal-cut or American-cut:   Proportions and facet angles calculated by Marcel Tolkowsky to maximize brilliancy in a round gemstone. The table is 53% of the stones diameter; depth is 60.3%; crown 16.2%; pavilion 43.1%; and the girdle 1%.

Illusion setting:   A prong setting with a wide rim of white gold surrounding the gemstone, either highly polished to act as a mirror or cut up to look like gemstone facets. This setting appears as a continuation of the stone. The purpose is to create the illusion that the stone is larger than its actual size.

Imitation:   Something derived or copied from an original.

Imperfection:   A term used to refer to any internal or external flaw on a cut and polished gemstone.

Inclusion:   Any visible internal foreign object in a diamond is called an inclusion.

Internally flawless:   Describes a gemstone without any internal flaws, but has minor surface blemishes, such as such as scratches, etc. Usually such stones can be improved to "flawless" by re-polishing at a small loss of weight.

Irradiated diamond:   A diamond that has been subjected to bombardment by electrons, neutrons, or other atomic particles. Its purpose is to make the diamond's color more attractive and desirable.

J

Jager:   Term for a fine white diamond.

Jet:   Black fossil coal or wood that can be easily carved into jewelry. Some jet is polished and some has an opaque appearance. Jet became fashionable for mourning jewelry in the nineteenth-century when Queen Victoria went into mourning after the deaths of her husband and mother.

K

Karat:   A unit of weight to express the quality of a gold alloy, such as 18 karat or 14 karat. Pure gold is 24 karat. The word is spelled karat when applied to precious metals, and carat when applied to weight of gemstones.

Kimberlite:   A volcanic rock that may contain diamonds.

Knife-edge girdle:   A very thin, knife-edge like girdle on a gemstone. Not very desirable, since such a girdle is vulnerable to chipping.

Knot:   A diamond crystal within a diamond that is most noticeable at the surface of a stone and stands out as a small, raised surface or bump.

L

Lab-Created:   Made in a laboratory or laboratory manufacturing setting.

Lapidary:   One who cuts, polishes, or engraves gems.   A dealer in precious or semiprecious stones.   Of or relating to precious stones or the art of working with them.

Laser drilling:   Technique of enhancing the clarity of a diamond by providing access for bleaching agents to inclusions in a diamond.

Lead glass:   A glass that contains a large proportion of lead oxide. The addition of this oxide raises the refractive index and makes it much more brilliant than ordinary glass.

Light-field illumination:   A type of illumination that places the light source directly behind gemstone being observed.

Light yellow:   A term used by some dealers to cover a wide range of colors in the low end of the diamond color-grading scale. These stones show a very obvious yellow tint.

Loupe:   A small jeweler's magnifying glass. Most have a two lens (corrected) system and are of 10x power.

"Loupe clean":   A misleading term, since it suggests that no flaws are visible at less than 10X power magnification.

Luster:   The quality of light reflected from the diamond.

M

Make:   A trade term that refers to the proportions and finish of a polished diamond, as in good make or poor make.

Man Made:   Made by humans rather than occurring in nature.

Manufactured:   To make or process (a raw material) into a finished product.

Marquise cut:   A style of diamond cutting in which the outline of the girdle is boat shaped.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Master stones:   Polished diamonds, of known color grades that are used as comparison when grading diamonds for body color.

Melange:   A mixed parcel of diamonds of varying grades and sizes.

Melee:   Smallish diamonds.

Millegrain:   A millegrain is a type of setting in a gemstone is secured with tiny beads of metal.   Millegrain is also used as a decorative technique on its own, without gemstones.

Milky diamond:   A diamond that has a milky, dull or hazy appearance, usually caused by clouds of microscopic inclusions.

Moe gauge:   A caliper-type gauge that, together with accompanying tables, is used to estimate the approximate weight of a mounted round brilliant-cut diamond by measuring its diameter and depth.

Mohs' scale:   The most commonly used scale of relative hardness of minerals:   diamonds, 10; corundum (ruby and sapphire), 9; topaz, 8; quartz, 7; feldspar, 6; apatite, 5; fluorite, 4; calcite, 3; gypsum, 2; talc, 1.

Mother of pearl:   Mother of pearl is the common name for iridescent nacre, a blend of minerals that are secreted by oysters and other mollusks and deposited inside their shells, coating and protecting their bodies from parasites and foreign objects.

N

Natural:   A term for a portion of the original surface of a rough diamond that is sometimes left by the cutter on a polished stone (usually on the girdle) to preserve a larger size and carat weight.

Natural gemstone:   A gemstone formed in nature, with no assistance from humans.

Natural pearl:   A pearl that begins as a piece of grit or other foreign substance that makes its way into the shell of a marine or freshwater mollusk (oysters, clams). A defense mechanism kicks-in to coat the particle with layer after layer of a substance called nacre, eventually forming a pearl.

Nick:   A minor chip out of the surface of a polished diamond, usually caused by a light blow.

O

Off-color diamond:   Any diamond that has a tinge of undesirable color, especially yellowish, brownish, or grayish.

Oiling:   Oiling is used to seal a stone such as opal from water loss. It is used to fill fissures on the surface of emeralds, improving their clarity.

Old-mine cut:   An early form of a brilliant-cut with a nearly square or cushion-shape outline. Not to be confused with European-cut.

Old-miner:   Abbreviation of old-mine cut.

Opal:   An amorphous mineral. In great demand as a gemstone because of its unique display of multiple colors.

Organic jewelry:   Jewelry made from items that were once living organisms or were produced by living organisms.  

Oval cut:   A brilliant style of cutting in which the outline is elliptical or oval.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

P

Pave setting:   A number of small stones set (paved) very close together, so as to show the least amount of metal. The stones are fitted into drilled holes and metal beads (small prongs) are pushed over the edge of the stones to hold them.

Pavilion (or base):   The pavilion is the bottom portion of a cut stone, beginning at the girdle and going to the point at its end.

Pearl knot:   Knots that are tied between pearls to keep them from rubbing against each other and damaging their nacre, the iridescent layer we see on the surface of pearls.   Knots also keep pearls more secure by acting as security stoppers-if a beaded strand breaks you might lose one or two but the knots will keep most of the pearls from falling off the strand.

Pear-shape cut:   A variation of the brilliant cut, having a pear-shaped girdle outline.   (For more detailed information see "Learning About Gemstone Cuts" in the DNL Information And Education Center)

Peridot:   A yellowish-green gemstone.

Platinum:   A soft, heavy, light gray precious metal.

Point:   One carat of diamonds is divided into one-hundred parts. Each one-hundredth being called a point ; e.g., one third of a carat (or 0.33 ct.) is called 33 points, a half carat (0.50 ct.) is called 50 points, etc.

Polished:   A finished cut gemstone.

Polished girdle:   A girdle that has been lapped (polished) into a smooth, polished surface, or more commonly into a series of flat, polished facets, as opposed to a dull-looking unpolished girdle.

Practical fine cut brilliant:   This cut originated from practice and serves as the standard cut for judging proportions in Germany. Respective of the girdle diameter, the crown height is 14.4%, the pavilion depth is 43.2%, the table diameter is 56.0%, and the crown height to pavilion depth ratio is 1:   3.00.  The crown angle is 33.2 degree and the pavilion angle is 40.8 degrees.

Prong:   The projection of metal that overlaps the edge of a stone and secures it to the setting.

Prong setting:   The prong setting, sometimes called a claw setting, is the most commonly used gemstone setting and is especially popular for solitaire engagement rings. To create the setting, a gem is inserted into three or more metal prongs that form a basket-like base, and then the ends of the prongs are bent over and shaped so that they rest against the gem to hold it snugly in place.

Premier:   Diamond from the Premier Mines; as commonly used, diamond having an oily luster or false color.

Proportions:   The distribution of mass of a polished gem above and below the girdle. The proportions are mathematically derived for the optimum treatment of light. Proper proportions are the most important factor in bringing out the beauty of a polished gemstone.

Q

Quartz:   The most common and widely known mineral. It includes many varieties of gemstones in a great variety of colors. Among the best known are amethyst, citrine, smoky-quartz, aventurine, agate, and tiger's-eye.

R

Re-cutting:   Refinishing a polished stone to improve its clarity grade or to update and modernize an old style cut.

Red diamond:   The rarest of all fancy-colored diamonds. Ruby red stones are virtually unknown. Most so-called red diamonds are actually reddish-brown, rose-colored, or pale pink stones.

Refractive index (R.I.):   The measurement of how much a light ray is bent and reflected as it enters or leaves a gemstone. Generally, the higher the R.I. the greater the brilliancy of the stone.

Rhodium:   A metal of the platinum group. Frequently used to plate silver to prevent tarnish, or to plate white gold to resemble platinum.

Rock crystal:   Transparent colorless quartz sometimes referred to as "Herkimer diamonds."

Rose cut:   An early style of cutting diamonds, probably originated in India. The base (back) is usually flat and the top (front) is slightly dome-shaped and covered with a varied number of triangular facets that terminate in a point, much like a shallow sided pyramid.

Rouge:   Jewelers rouge (Iron oxide), a buffing compound for polishing gold.

Rough diamond:   A diamond in its natural, uncut or unpolished state.

Ruby:   The red variety of corundum. Intense, medium to medium dark purplish red (pigeon's blood) is best, intense red is fine and dark red is less desirable.  

S

Sapphire:     Any corundum other than ruby, but generally referring to the blue variety. Other colors are pink sapphire, purple sapphire, green sapphire, etc.

Scintillation:   Scintillation (flashing or twinkling of light) in gemstones refer to the alternating display of reflections from the polished facets when in motion.

Semiprecious:   A classification of all gemstones other than the so-called precious stones; i.e., diamond, ruby, emerald and sapphire.

Setting:   Setting or mounting specifically refers to the portion that actually holds the stone as opposed to the rest of the jewelry item it is attached to.

Shallow stone:   A diamond on which the pavilion facets are at an angle of less than 39 or 40 degrees to the girdle plane. The less the angle the greater the loss of brilliancy. The diamond will have a very glassy appearance and is usually called a fisheye.

Silver:   A white precious metal. It is used in the manufacture of jewelry, silverware, coins, photography, electronics, etc. It is harder than gold, softer than copper, more malleable and ductile than any other metal except gold, and an excellent conductor of heat and electricity.

Simulated:   Made in resemblance of or as a substitute for another.

Simulated stone:   Any lab-created or manufactured compound that imitates a natural gemstone in appearance.

Single cut:   A simple form of cutting for small diamonds. Consists of a table, eight bezel (top) facets, eight pavilion (bottom) facets.

Slightly imperfect:   A grade of relative imperfection in a diamond. Abbreviated SI, it is more flawed than very slightly imperfect (VS) but less than imperfect (I).

Solitaire:   A ring containing a single center gem, with or without small gemstones in the shank.

Spratling silver:   Named for William Spratling, who established a thriving silver industry in Taxco, Mexico, with inspiration from the artistic accomplishments of early cultures of that country.

Spread stone:   A diamond that has been cut with a large table and a thin crown, to retain greater weight than is possible by using ideal proportions. Also called a fish eye because the larger diameter suggests more weight than it actually has.

Star facets:   The eight triangular facets that bound the table of a round brilliant-cut diamond between the main bezel facets.

Sterling silver:   A metallic alloy consisting of 92 1/2% silver and 7 1/2% copper. Sterling silver is usually stamped sterling or 925. The word sterling is derived from Easterling, the name of a 20th-century group of German traders who paid for merchandise with a silver coin, the content of which they rigidly controlled at a time when debasement of coins was common.

Surat, India:   A notorious polluted city that is a major diamond cutting center, where roads are lined with flimsy shanties to house workers.   Diamond cutters are recruited as young children by traveling agents going from village to village.   Sharp young eyes are much prized.   Child labor is illegal in India, but the law is ignored. Journalists have documented 8 year-olds working with dangerous cutting wheels, breathing in the black diamond dust.   More than 64,000 children work in the India diamond cutting industry.   20 to 40 cents is paid on a piece work basis for the cutting and polishing a small diamond, which is shocking considering what diamonds sell for to consumers in America.   In 2001, 85% by weight of the world's gem quality diamonds were cut and polished in India.

Syndicate:   In-trade reference to the corporate mechanisms by which De Beers controls the marketing and pricing of most of the world's rough diamonds.

Synthetic:   Produced by synthesis, especially not of natural origin.

T

Table:   The large facet that caps the crown of a polished diamond.

Tanzanite:   Tanzanite was first introduced in 1969 and is found only in a relative small, approximately, five square mile area near the Kilimanjaro Airport in Tanzania. Tanzanite comes in various shades of violet-blue. The less expensive colors range toward violet, a light purplish blue. The best and more expensive colors are a rich deep blue with just a hint of violet.

Topaz:   A gemstone best known for its beautiful transparent yellow-brown color, also very popular in pink, light blue and reddish-brown colors.

Tourmaline:   A gem best known for its green and pink stones.

Treated (altered) diamond:   A diamond that has been coated, laser drilled, filled or otherwise treated to improve or alter its color or appearance.

Tumbled stones:   These stones are free-form lumps that are mass- finished by tumbling them in a drum with water and abrasive particles.

Tycoon cut:   The Tycoon cut is a departure from the other branded rectangle shapes with a radical top design which is reminiscent of the early French cut.   The secret of this brilliant stone is the nine crown facet design which creates a diamond-shaped table.  It's like having a diamond within a diamond.

V

Vermeil:   A product that is made from a base of sterling silver that is coated or plated on its surfaces with gold of at least 10K and at least 2.5 microns thick (100/1,000,000 inch).   The term vermeil cannot be used if the sterling is covered with a base metal before being coated with gold unless the presence of the base metal is disclosed.

Very slightly imperfect:   A clarity grade between very, very slightly imperfect and slightly imperfect. Abbreviated as VS.

Very, very slightly imperfect:   The imperfection grade that is just below flawless. Abbreviated as VVS.