Diamond Glossary

DIAMOND GUIDE – DIAMOND GLOSSARY

Knowledge of diamonds will bring you to further questions and make you inquisitive about the various terminologies associated with diamonds and its jewelry. To quench this thirst of knowing more, you can visit our Diamond Glossary.

Term

Description

Abrasion Very small and tiny sketches on facet joints which fabricates white hairy lines instead of sharp crisp facet edges. Antique and other old or heavily used diamonds can have abrasions.
Adamantine This refers to the surface luster and shine of a diamond.
Adamas The word Diamond comes from this ancient Greek word ‘Adamas’, which means unconquerable.
Alluvial Stones those have been sourced from alluvial deposits in river beds or transported by water and deposited in seas and lakes. Many gems, including diamonds, are found in alluvial deposits and Alluvial diamonds are usually of gem quality.
American Cut Marcel Tolkowsky’s mathematically calculated ideal proportions and facet angles, to produce maximum brilliancy consistent with a high degree of fire in a round diamond brilliant, are known as American Cut or Ideal Cut.
Appraisal Appraisal is a written statement based on estimated retail replacement value of the polished diamonds. Appraisal is mainly used for insurance purposes and should be updated after every few years.
Artificial Diamond Artificial diamonds are produced by man in laboratory and mainly used in making artificial jewelry.
Baguette Baguette is a French word meaning ‘Rod’. It is a step cut for small rectangular shaped diamonds and other gemstones.
Baroque Diamonds and other gemstones which are irregular in shape or available in freeform.
Bearded girdle Small or tiny, numerous hair like fractures / cracks around the girdle extending into the stone.
Bezel A facet on the Crown, or slopping surface just above the girdle of the Diamond.
Bezel Facets On a round brilliant-cut diamond, these eight large, four-sided facets on the crown where the upper points join the table and the lower points join the girdle.
Black Diamond A diamond with very dark color like dark gray, very dark green or truly black is referred in the trade as ‘black diamond’.
Blemish An external mark or surface imperfection on a diamond. For example, a nick, abrasion, knot, scratch, minor crack or fissure (cavity), or a poor polish. A natural or an extra facet is also considered a blemish.
Blue Diamond A diamond with blue color is very rare and valuable although fluorescence diamond that shows a blue color in daylight is comparatively common.
Blue White A term that has been used for near white diamonds with strong blue fluorescence.
Body Color A diamond’s actual color which can be observed when examined under a diffused light against a hue less background. The diffused light eliminates glaring reflections and dispersion, which would otherwise confuse the color determination.
Bort Industrial grade diamonds generally used as drill points.
Bow Tie Effect An optical effect due to a shadowy area visible in some fancy shapes, caused by light leaking out from the bottom of the Diamond. This effect can be minimized by careful cutting using best proportions and angles.
Briefjes A special kind of paper, which is used to contain diamonds. This paper has several inner leaves of wrinkled bluish paper, which gives whiter look to the diamonds.
Brilliance Brilliance describes the reflections of white light returned to the eye from a diamond. Brilliance is produced primarily when light enters through the table, reaches the pavilion facets, and is then reflected back out through the table. Brilliance is the effect that makes diamonds unique among all other gemstones. Although all other gemstones also display brilliance, but none have the power to equal the extent of diamond’s light-reflecting power. The major factors that affect the amount of brilliancy in a gem are refractive index, proportions, polish and transparency.
Brilliant Cut Brilliant Cut is the most common style of diamond cutting, which is also used for almost all other gemstones. It is called a brilliant cut because it is designed to maximize brilliance. The standard round brilliant cut consists of a total of 58 facets which covers 1 table, 8 bezel facets, 8 star facets and 16 upper-girdle facets on the crown; and 8 pavilion facets, 16 lower-girdle facets, and usually a culet on the pavilion, or base. Brilliant cut diamonds normally comes in round shape, but there are modified variants in other shapes also. Sometimes the term “Brilliant Cut” is also used as a synonym for “Round Diamond.”
Briolette This term is used for a long teardrop shaped diamond with rose cut facets, which sometimes is also drilled to be used as a pendant.
Broker A person who is a specialist in introducing diamond buyers and sellers, and earns his commission on the value of deals done between diamond buyers and sellers.
Brown Diamond A diamond with attractive or vivid brown color is rare and considered as fancy colored stone.
Bruise An inclusion which consists surface crumbling and normally accompanied by tiny, root like feathers. This inclusion is usually caused by external trauma such as a knock or a blow.
Bruting Bruting is the process of rounding a diamond to form its girdle. This is usually done by grinding one diamond against another on a rotating wheel. It is also known as girdling or rounding.
Bubble Any transparent inclusion which consists a tiny crystal or a grain of a different mineral.
Burnt A facet may appear burnt or foggy, as a result of the cutter polishing the facet against the grain, or otherwise allowing the diamond to overheat causing the surface to oxydise.
Cachette A sealed packet with approved status containing diamonds bought in a trade deal, along with agreed payment terms. This word comes from French word ‘Cacher’ which means to seal.
Cairo Star It is a variation on the modern round brilliant cut with 74 facets.
Canary A term used for diamonds with an intense yellow hue. The yellow color may appear with very slight greenish or slight orangey shade. Such diamonds are considered as Fancy and also called Fancy Yellow.
Carat The term Carat is used as a standard unit of measurement of the weight of diamonds and most other gemstones. The word comes from the carob beans which are known for its consistent weight and were used in ancient times to measure diamonds and other gemstones. One carat (ct.) equals 200 milligrams, or 0.2 grams (1/5 of a gram), or 1/142 of an ounce. There are 100 points in a carat. If all other factors are equal, the more a diamond weighs, the more valuable it will be. It is sometimes incorrectly spelled ‘Karat’, but Karat refers only to the fineness of pure gold and gold alloys.
Carbon Diamonds are composed of carbon entirely, or almost entirely.
Carbon Spot An inclusion or imperfection in a diamond that appears black, which is caused by the addition of the small particles of graphite or another mineral. In most cases, these black inclusions are not visible to the naked eye, and do not affect the brilliance of the diamond.
Cavity  A type of inclusion consisting of a large or deep opening in the diamond. It may be either internal or extending to the surface cause by cleavage or by a blow. Internal cavities may naturally contain gas, liquid, solid, a combination of two or three of these.
Centenary A large and famous diamond, unveiled recently in 1988. It was 599 carats in the rough, and cut to a gem weighing over 273 carats. It is second only to the Cullinan for its combination of size and quality.
Certificate A statement or document issued and certified by a gemological laboratory which consists the genuineness of a diamond or other gemstone along with the quality and other characteristics.
Change of Color Sometimes diamond changes color or appears with a different color in different types of light. This is caused by selective absorption and/or transmission of the specific type of light to which the stone is exposed.
Channel Setting A setting style or method in channel form where no metal is displayed between stones.
Chip A curved break or absence of a tiny piece of a diamond, caused by normal wear and tear, or by cutting.
Clarity Clarity is one of the four value factors of a diamond which describes the absence or presence of flaws inside or on the surface of a diamond. Diamonds are graded on a scale from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (eye visible inclusions or blemishes). If other factors are equal, flawless stones are most valuable.
Clarity Enhancement A process which is used to improve the apparent clarity of a diamond usually by filling fissures or fractures with a transparent substance like glass. Also known as ‘Fracture Filled’.
Clean A word used by some jewelers unofficially or informally which means flawless, or at least internal flawless.
Cleaning Cleaning of a diamond is essential to bring or maintain its shine and brilliance. At the mines, various methods are used to clean rough diamonds like boiling in acid etc. For domestic cleaning of diamonds, warm soapy water works well.
Cleavage The tendency of crystalline minerals, such as diamond, to break in one or more definite directions, producing more or less smooth surfaces. A cleavage may be caused by inherent internal strain or by a sharp blow. Cleavage is one of the two methods used by diamond cutters to split rough diamond crystals in preparation for the cutting process. The other method is sawing.
Closed Culet A culet on a diamond which consist a point rather than a facet. That point is too small to be resolved with the unaided eye and can be seen only under 10X magnification.
Cloud A group of a number of extremely tiny white inclusions which gives a ‘cloudy’ or ‘milky’ appearance under 10x magnification. These clouds cannot be seen with the naked eye and generally does not significantly impact a diamond’s clarity grade.
Cluster This term is used for diamond ring or any other jewelry containing a number of diamonds. Cluster is also used for a number of kimberlite pipes occurring in close proximity.
Coated Diamond A diamond colored by a surface coating which masks the diamond’s true body color. Coating may be used extensively to entire pavilion or limited to one or two pavilion facets or a spot on the girdle.
Color Color is one of the four value factors of a diamond. Diamonds are ranked on a color scale from ‘D’ (colorless) to ‘Z’ (noticeable tint of color, typically yellow or brown). Diamonds with saturation greater than ‘Z’ color are considered Fancy Colored Diamonds such as blue, pink, purple, red etc. and are graded on a separate scale.
Color Grading A system of grading diamond colors based on their colorlessness (for other than fancy diamonds) or their spectral hue, depth of color or purity of color (for fancy color diamonds).
Colorless Colorless diamonds are white or transparent diamonds and promoted as the best, but only because other attractive colors are extremely rare.
Color Enhancement Color enhancement is the improvement process of a diamond’s color mainly by irradiation and HPHT (High Pressure, High Temperature). Sometimes color coating is also used to enhance the diamond’s color which is not considered as best enhancement way.
Commercial This term is used for medium to low quality diamonds and opposite to fine gem quality.
Commercial White Commercial White is a dealers’ term for ‘off-white’ diamonds.
Comparison Sometimes gems laboratories perform their grading by comparing one stone with another stone of known quality. This comparison is useful to consumers who are not well aware of diamond quality factors.
Created A description of synthetic diamonds opposite to natural ones.
Critical Angle Critical angle is the largest angle measured from the normal angle from which light can escape, is an optically dense substance, and the smallest angle to the normal angle at which light is totally reflected within the dense substance.
Crown The upper portion of a cut diamond above the girdle which consists of a large flat area on top known as table, and several facets below it.
Crown Angle The angle between the girdle and diamond’s bezel / concentric facets is known as crown angle. This gentle slope of the facets that surround the table helps to create the dispersion or fire in a diamond. White light enters from the crown angles and brakes up into its spectral hues which ultimately enhance the brilliance of a diamond.
Crown Height The height or depth of the crown of a diamond, above the girdle.
Crystal A diamond is a crystal which is formed entirely or almost entirely by carbon. Sometimes crystal is also considered as a type of inclusion which is a mineral deposit trapped inside the diamond.
Cube A cube is a rough diamond with approximately cubic shape. Gem-quality cube-shaped diamond crystals are very rare in nature and considered as collector’s items.
Culet The smallest facet at the bottom of most round or brilliant cut diamonds is known as culet. Its purpose is to protect the tip of the pavilion from being chipped or damaged. Most modern shapes have either no culet at all, or a small or very small culet.
Cullinan, Cullinan I, Cullinan II The Cullinan was the largest Diamond Crystal ever found with weight of 3,106 carats in the rough and was cut into 9 major stones and 96 smaller stones. Out of these 9 major stones, Cullinan I is the largest stone with 530.20 carats and Cullinan II is the second largest stone with 317.40 carats. Both of these stones are now part of British Crown Jewels.
Cushion A shape of diamond, which ranges from square to rectangular and it has rounded corners and larger facets to increase its brilliance. Cushion Cut diamonds are also known as “pillow cut” diamonds.
Cut Cut is one of the major value factors of a diamond. The cut, also called make, of a diamond refers to the proportions and finish given to the polished diamond by the diamond cutter. Proportions are the size and angle relationships between the facets and different parts of the diamond. It is the only man-made contribution to a diamond’s beauty and value.
Cutter The person who cuts and polishes rough diamonds and convert them into finished diamonds.
Cutting The process of cutting, grinding or polishing rough diamonds and convert them into finished diamonds.
CZ CZ denotes cubic zirconium, a widely used simulant, an imitation for a natural diamond. Although CZ is easily detectable by it’s 80% higher weight than a diamond of the same proportions or by thermal conductivity testing.
Deep This usually means a diamond which has been cut too deep. This deep cut maximizes weight but sacrifices brilliance.
Depth The height of a diamond from the table to the culet which is measured in millimeters.
Depth Percentage The depth percentage, which expresses how deep the diamond is in comparison to how wide it is. In other words, the depth of the diamond is divided by the average width. This depth percentage of a diamond is important to its brilliance and value. The pavilion should be deep enough to allow light to bounce around inside the diamond and be reflecting out to the eye at the proper angle.
Detection Detection is the ability to identify diamond imitations, synthetics and treatments.
Diameter The width of the diamond, as measured across the widest part of the girdle.
Diamond The word “diamond” comes from the Greek word “Adamas”, meaning “Unconquerable”. Diamond is composed of carbon that crystallizes in the “cubic,” or “isometric,” crystal system. It is the hardest known substance in the world (10 on Mohs’ scale). The Diamond is uniquely resistant to damage by heat or scratching, and can be cut or polished only by another diamond. It occurs in colors ranging from colorless to yellow, brown, orange, green, blue, and violet.
Diamond Cutter The person who cuts and polishes rough diamonds and convert them into finished diamonds.
Diamond Cutting The process of cutting, grinding or polishing rough diamonds and convert them into finished diamonds.
Diamond Gauge An instrument that is used to measure a diamond’s length, width and depth in millimeters.
Diamond Saw A saw used for dividing or separating diamonds.
Direction Hardness is directional in diamonds and it is important for cutting. The optimal direction of cutting and polishing depends on the optical axes of diamonds.
Dispersion Dispersion is the ability of a diamond or other gemstone, to separate white light into the colors of the spectrum. Diamond has the highest dispersion (.044) of any natural, colorless gem.
Draw, Draw Color A diamond which is not pure white (colorless) is often said to draw color.
Drill Bit Due to diamond’s hardness, it is often used in high quality or high performance drill bits.
Drill, Drilling Now laser is used to drill a diamond neatly for removing inclusions as well as drilling could also be done to create a diamond bead.
Durability Durability describes a diamond’s resistance power against scratches and cracks due to wear. The durability of a diamond depends on its hardness, toughness and stability.
Dust Very tiny rough diamonds and generally used as abrasives. It is also known as diamond powder.
Emerald Cut Emerald Cut diamond is a square or rectangular shape stone with cut corners. This is also known as Step Cut because it has rows of facets, usually 48 to 50, that resemble a staircase. Due to its larger, more open table, this shape highlights the clarity of a diamond but with fewer facets, this shape brings less brilliance than the other shapes.
Enhance,Enhanced,
Enhancement
Enhance or enhancement is the process to improve a diamond’s color or clarity by using various methods.
European Cut A European version of ‘ideal’ cut which was used and preferred in Europe although it was never adopted as a common form of cutting.  In this cut, diamond‘s proportions were worked out mathematically for light falling perpendicularly on the crown.
Extra Facet An additional facet placed onto a diamond, usually to remove a ‘natural’ or small surface blemish. This extra facet is not required by the cutting style and symmetry.
Eye Clean A term used in the jewelry industry to describe a diamond with no blemishes or inclusions that are visible to the unaided eye.
Face A term used for flat or plane surface, particularly in a rough diamond crystal.
Facet A plane, polished surface on a diamond which allows light to enter in a diamond and reflect off through different angles.
Faceted Girdle A girdle of a diamond that is lapped and polished for maximum surface reflection and has many flat planes around the circumference of the diamond.
Faceting Faceting is the process of placing facets on a diamond.
Fancy Cut, Fancy Shape Any shape of diamond other than the round brilliant shape is known as fancy cut or fancy shape. It includes marquise, emerald cut, heart shape, pear shape, etc.
Fancy Diamond Fancy Diamond is a Diamond with strong natural body color other than light yellow or light brown. Colored or fancy diamonds are very rare and valuable and available in various colors like blue, pink, purple, red etc.
Feather Feathers are small fractures in a diamond caused by the tremendous stress that the diamond suffered while it was growing underground. Under magnification, these small fractures appear very much like a feather.
Fill, Filled, Filling This refers to the practice of filling open fissures in diamonds, usually with glass.
Finish The term refers to the quality of polish and symmetry on a diamond.
Fire Fire refers flashes of spectrum colors seen in a diamond as the result of dispersion.
Fisheye A diamond with exceedingly shallow pavilion, which produces a glassy appearance and a noticeable dearth of brilliancy.
Fissure A crack or fracture or feather, which possibly reached to the surface of a diamond.
Flat A diamond with a very thin crown and pavilion which gives a flat effect.
Flaw Flaw refers to any internal or external imperfection on a diamond and usually includes feather, fissure, carbon spot, knot, etc.
Flawless Flawless is a term used for a diamond that is without any internal or external flaws when viewed by a trained eye under 10X magnification.
Fluorescence An effect in many diamonds that makes them glows in ultraviolet rays or light. Diamonds can fluoresce in a number of colors, mainly in blue and Fluorescence ratings include none, faint, slight, medium, strong and very strong. Faint to medium fluorescence is rarely detected under most lighting conditions which include sunlight also whereas strong or very strong fluorescence may make a diamond appear ‘milky’ or ‘oily’ in such lighting conditions. Fluorescence is not dangerous to the diamond or to its wearer. It is a unique and fascinating quality that occurs naturally in a number of gems and minerals.
Four Cs A phrase used to describe a diamond’s value characteristics which cover the four well-known factors affecting the price of a diamond. All these factors start with the letter ‘C’: cut, color, clarity, and carat weight.
Fracture A breaking or chipping in a diamond, which usually reached to the surface of a diamond and that is not in the direction of a cleavage plane.
Fracture Filling A diamond’s enhancement process in which cavity is filled in a diamond with an artificial substance like glass.
Full Cut Brilliant A full cut brilliant is a diamond usually with total of 58 facets, consisting of 32 facets and a table above the girdle and 24 facets and a culet below the girdle.
Gauge Any device or instrument which is used to calculate the weight of diamonds, by measuring or estimating physical dimensions like diameter, depth, length.
Gemologist A person with expertise in gemology is known as gemologist. There are many recognized courses available from various Gemological Institutes which offer study in gem identification, grading and pricing, as well as diamond grading and appraising.
Gemological Institute
of America (GIA)
Gemological Institute of America (GIA) was founded as non-profit organization in 1931 by Roger Shipley. GIA maintains the highest standards for grading diamonds and other precious gems and it has one of the world’s most-respected and well-regarded gemological laboratories. GIA has developed and standardize the diamond grading system that is used by nearly all other gem labs.
Gemstone A gemstone is a mineral or rock, which can be used in jewelry after cutting or faceting and polishing. Gemstones are diverse in their beauty and many gems are available in a stunning variety of colors. Most gemstones have little beauty in the rough state. They may look like ordinary rocks or pebbles. After a skilled cutting and polishing of a gem, full color and luster can be seen.
Girdle Girdle is the widest part or outer edge of the diamond 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 diamond’s grade. Most labs grade a girdle’s thickness, not its appearance and the descriptions of girdle thickness range as follows: extremely thin; thin; medium; slightly thick; thick; extremely thick.
Girdle Facet The 32 triangular facets that adjacent to the girdle on a brilliant cut or other diamond and split into 16 upper (crown) girdle facets, and 16 lower (pavilion) girdle facets. Sometimes facets are placed directly on the girdle, in which case the diamond is usually said to have a ‘faceted girdle’.
Girdle Thickness It is the measurement describing the percentage of the diamond’s average girdle diameter. The girdle thickness ranges as follows: extremely thin; thin; medium; slightly thick; thick; extremely thick.
Girdling Girdling is the process of giving a circular shape to a diamond. In this process, a diamond is held in a lathe, or in a cutting machine, and cut or shaped by another diamond, called a sharp.
Gold Gold is a yellow precious metal used in most jewelry with various alloys.
Grade A recognized measure of an aspect of diamond’s quality, mainly clarity and color.
Grading The process of evaluating a diamond, and allocating grades to it.
Grading Report A grading report or certificate is a statement, issued by an independent Gemological Laboratory, that at the time of evaluation, the Diamond in question has been examined, measured, and scrutinized by experienced Diamond Graders, using various gemological instruments, and determined to contain the characteristics as stated in the Report or Certificate. The grading report should accurately describe the proportions, weight, color, clarity, symmetry, polish and possible fluorescence seen in the diamond.
Grain Diamond crystals have different strength bonds in different directions and these directions are known as grain.
Grain Center A small area of intense crystal structure distortion which usually associated with pinpoints.
Graining Usually graining refers to internal irregular crystal growth which may appear milky like faint lines or streaks.
Gypsy Setting The gypsy setting is a recessed setting in which the stone is sunk into the metal and there are often engraved designs around the stone especially in star patterns. The gypsy setting is also known as the ‘star setting’.
Hardest Diamond is the hardest known naturally occurring substance on Earth.
Hardness The hardness of a diamond refers it’s resistance to scratching on a smooth surface. Diamond is the hardest known substance on Earth and it is graded 10 on Mohs’ scale of hardness. Hardness is directional in most gemstones.
Head Head refers part of the setting that holds the center stone or solitaire in place.
Heart Cut The Heart shaped diamond is a fancy cut diamond and essentially a pear-shaped with a cleft at the top and which typically contains 59 facets. Due to the complexity of the shape, skilled cutting is necessary to maintain the diamond’s brilliance. Generally people prefer a heart shape diamond for sentimental purposes. This shape is mostly used in pendants, but also suitable for most jewelry items.
Heat Treatment Heat treatment is the process in which heat is offered to a gemstone for the purpose of improving its color.
Hope diamond The Hope Diamond is the world’s largest deep blue diamond. It is famous for its striking color and infamous for its history of bringing bad luck to its owners. This attractive stone is also having a history of stolen and recovered, sold and resold, cut and recut. It is now on display at the Smithsonian Institute in Washington.
Hue Hue is an aspect of color such as pink, yellow, blue, green, etc. It is a primary factor in viewing and grading fancy colored diamonds.
Ideal Cut Theoretically perfect cutting proportions and facet angles calculated mathematically to produce maximum brilliancy consistent with a high degree of fire in a round brilliant cut diamond. Ideal cut is also known as American Cut.
IGI
(International Gemological
Institute)
IGI (International Gemological Institute) is an organization which offers a grading report for diamonds and other gemstones. IGI has laboratories located throughout the world, including New York, Antwerp, Mumbai, Bangkok and Tokyo.
Imitation Imitation is any diamond like material, either natural or artificial, which imitates a diamond. It is also known as simulant.
Imperfect The diamond imperfection grade at the low end of the ‘flawless-to-imperfect’ scale. An imperfect diamond contains any external blemish or internal inclusion or flaw that are visible to the unaided eye or that have a serious effect on the stone’s durability.
Included
Crystal
A diamond which contains a mineral crystal is known as included crystal.
Inclusion An internal imperfection or characteristic which reduces the clarity or brilliance of a diamond. Common diamond inclusions are feathers, crystals, fractures, needles, graining, pinpoints and cavities.
Industrial
Diamonds
Low grade or very small diamonds which are not perfect for jewelry use and are generally used in various industrial applications.
Internal
Graining
A diamond which contains internal irregular crystal growth is known as internal graining. It may appear milky like faint lines or streaks.
Internally
Flawless (IF)
A clarity grade which refers no inclusions and only insignificant surface blemishes.
Irradiated
diamond
A diamond which has been exposed to radiation usually to improve its color.
Karat, Karat
Weight
Karat is the American spelling of carat which is now only used for gold or gold alloys weight whereas English spelling carat is used in respect of weight of diamonds or other gemstones. Karat is always based on pure 24 karat gold and if a jewelry item contains 18 karat gold that means it has eighteen parts pure gold and six parts other metal alloys.
Kimberlite Rock The yellow or blue rock which forms diamond pipes, and in which most diamond is found.
Knot An included diamond crystal which reaches to the surface of a polished diamond. This knot is difficult to cut or polish because of twinning, negative crystal growth, or similar feature.
Kohinoor,
Koh-i-noor
The name of Koh-i-noor means “Mountain of Light”. It is an Oval Shaped Brilliant cut diamond with 108.93 carat weight. This diamond was presented to Queen Victoria in 1850 to mark the 250th anniversary of the founding of the East India Company. It is now on display with the British Crown Jewels in the Tower of London.
Laser Drill Hole A tiny tube which is created in a diamond by laser drilling to treat a diamond. It is one of the few man-made inclusions that can occur inside a diamond. The surface opening may resemble a pit, while the tube usually looks needle like.
Laser Drilling A diamond enhancement technique by a laser which is used to drill a diamond to remove inclusions. BY using this laser drilling technique, clarity grade of a diamond can be raised.
Length-to-width ratio A comparison of the length and width of the girdle outline on fancy shaped diamonds. It is used to analyze the outline of fancy shapes only and it is never applied to round diamonds. The ratio is found by dividing the length of the diamond by the width where diamond width is always stated as 1. This ratio is simply a matter of personal aesthetic preferences and there is no defined ideal ratio for any of the fancy shaped diamonds.
Light Brown A diamond which is not intense enough to be considered as fancy brown and often appear quite white.
Light Yellow A diamond with light yellow tint is considered as fancy yellow.
Loupe Loupe is a French word for magnifying glass. It is a small magnifying lens used to examine diamonds. 10X magnification is the standard.
Lower Girdle Facet A diamond facet on the pavilion of a round brilliant cut just below the girdle.
Luster The quality of reflected and refracted light from the surface of a diamond or gemstone or pearl. Luster is mainly dependent on stone’s surface (polish) and the reflective index of the mineral. Luster can be described as: adamantine, pearly, greasy, metallic, silky, resinous, vitreous, earthy (also known as dull) and waxy.
Main Facets The large crown and pavilion facets of a brilliant-cut diamond whereas on step-cut stone, the center row of facets on the pavilion.
Make Make is a trade term refers to the proportions, symmetry and polish of a diamond or a gemstone.
Marquise Cut The Marquise Cut is a traditional shape having elongated ends at both edges. The pointed ends make this shape the most fragile and the most expensive of brilliant style cuts. It has a total of 56 facets and construction of facet requires a lot of experience and delicacy of the sharp points demands utmost precaution. Now-a-days this shape is very popular for engagement rings.
Melee This term is used to describe small brilliant-cut diamonds under .20 carat. Generally, these small diamonds or gemstones are used to embellish mountings, setting or larger stones.
Mine A place where diamonds are extracted from the ground, by using various methods of mining like open cast, deep pit etc.
Mineral Mineral is a naturally occurring, inorganic element of the Earth with a consistent atomic structure and chemical composition.
Modern Brilliant
Cut
It is a round brilliant cut unless otherwise stated normally with 58 facets including the culet and polished using relatively modern theory. This shape is considered as ideal for a diamond because it maximizes a stone’s sparkle and brilliance.
Modified Brilliant
Cut
A diamond cut in a shape or style other than round brilliant cut, such as oval, pear, marquise, heart, princess, radiant, or baguette.
Mohs scale It is a ten point scale to find mineral hardness which is devised by Friedrich Mohs, a German mineralogist, in the 19th century. The diamond is the hardest of all known natural substances and it scores 10 on Mohs Scale.
Moissanite Transparent silicon carbide, which is a rare crystal in nature, marketed as a diamond stimulant. It is named after Henri Moissan, famous French scientist. Its double refraction is one of the few differences with a diamond whereas thermal conductivity is almost equal.
Molecule Diamonds are composed of large molecules or particles of carbon atoms with strong bonds in all planes.
Mounting The process of making a ring or other piece of jewelry into which gemstones will be set.
Natural A small portion of the original surface of a rough diamond left by the cutter when polishing and faceting a diamond which is frequently on or near the girdle. This is generally the sign of a cutter attempting to maximize the weight retention of the rough diamond. Usually naturals do not affect the clarity grade and in most cases, they are undetectable to the naked eye.
Needle A long, thin and sharp crystal inclusion which looks like a tiny rod.
Nick A minor chip out of the surface of a diamond, usually found near or on the girdle of the stone.
Off Make A poorly proportioned Diamond, particularly with poor symmetry.
Old European Cut The earliest known form of brilliant cut diamond with a very small table, a heavy crown, and usually great overall depth. This is also known as old mine cut.
Opaque Opaque refers to the transparency of a diamond. Generally opaque material does not transmit light.
Orange A very rare and attractive fancy color of diamond.
Orloff Orloff is a Mogul-Cut Rose diamond with 189.62 carat weight. It is with exceptionally pure clarity and slightly bluish green color. According to a tale, the Orloff was set as the eye of Vishnu’s idol (one of the Hindu Gods) in the innermost sanctuary temple in Sriangam and was stolen in the year 1700 by a French deserter disguised as a Hindu.
Oval Cut The Oval Cut is a beautiful Fancy shape which offers great brilliance and fire through its 56 facets. This is an elongated version of round cut, provides the same brightness which comes from a round brilliant shaped diamond.
Parcel Parcel is a packed paper envelop for diamonds which is purchased by buyer without selection of containing diamonds. Although sometimes buyer is permitted to reject a small number of diamond.
Paste Powder of very small diamonds in paste form, which is made with oil or any other binder and used as an abrasive for cutting and polishing any material including other diamonds.
Pave An attractive style of jewelry setting in which numerous small diamonds are mounted as close together as possible to create a sparkly diamond shell. This setting style covers the whole piece of jewelry with diamond crust and conceals the metal under it.
Pavilion Pavilion is the lower part of a diamond, below the girdle.
Pavilion Angle This is the angle between the main pavilion facets and the girdle. In a diamond, this is the most important dimension and ideal pavilion angle should be around 40.75° to 41°.
Pavilion
Main Facet
The eight facets found on the pavilion of a round brilliant diamond.
Pear Cut The Pear Cut is a fancy shape diamond that looks like a teardrop due to its single point and rounded end with 56 to 58 facets. This shape is popular for its uniqueness and brilliance.
Phosphor-
escence
A diamond, which is exposed to daylight, ultra-violet or other light, continues to glow after the light source has been removed.
Pick The term pick is used when seller permits buyer to select one or more diamonds from a parcel.
Pink Diamond Pink is one of the rarest and most desirable fancy colors for a diamond. Any diamond with pale reddish, purplish-red and purplish hue is known as pink diamond.
Pinpoint Tiny or very small inclusions, of pinpoint size, internal to a diamond. Whereas a cluster of pinpoints can form a cloud.
Pipe This term is used for vertical, columnar rocks that are originated due to lava flow and after that cooled and solidified in the neck of a volcano.  When these rock masses consist of kimberlite, they often contain diamonds.
Pit A tiny opening or surface mark on a diamond which often looks like a white dot.
Platinum Platinum is a silvery gray precious metal often used for setting or mounting high quality diamonds.
Plotting Diagram A graphical representation or a diagram in a diamond certificate that illustrates the facets of a diamond as well as the approximate locations and types of internal and external characteristics. These characteristics can be spotted as internal and external by the different colors generally red and green.
Point A unit of measurement which is used to describe the weight of diamonds where one point is equivalent to one-hundredth of a carat. For example, a 1/2 carat diamond weighs 50 points.
Polish Polish is considered as smoothness of the surface of a fashioned diamond in which optical reflection is maximized. Generally a polished diamond does not show visible wheel marks or burn marks under 10X magnification. Polish is an indicator of the quality of diamond’s cut which is graded as Ideal, Excellent, Very Good, Good, Fair or Poor.
Polishing The process of polish which converts a diamond’s rough or irregular surface to a smooth surface by using various methods.
Polished Girdle A girdle that is polished or lapped to yield a lustrous and highly reflective surface.
Polish Lines Polish lines refer tiny or faint surface lines which are visible due to imperfect polishing or irregularities in crystal structure.
Polish Mark A burn mark or surface clouding on a diamond caused by excessive heat while grinding or polishing.
Powder The term powder refers to very small diamonds used for polishing other diamonds or materials.
Precious,
Precious Stone
The term precious is used for stones as well as metal. Stones those are highly valuable for their hardness and rarity, are known as precious stones. Precious stones include diamonds, emeralds, rubies, and sapphires.
Price Price of a diamond is extremely variable and based on all aspects of quality.
Princess Cut The princess cut is a fancy shape diamond which has pointed corners and square in shape. The ideal princess cut will have length to width ratio is as close to 1.00:1.00 as possible, as princess cut diamonds can range from this perfect square through to almost rectangular. This cut is the most popular non-round diamond cut.
Prong Setting Prong setting is the most frequently used method of setting diamonds into jewelry. This setting usually consists of four or six small metal tips or claws to hold the diamond tightly. This setting allows maximum amount of light to enter in a diamond from all angles and because of this, stone appears more brilliant and larger than its actual size.
Proportion The consideration of each part of a diamond in relation to all other parts. Proportion is an important quality element which evaluates the overall shape of a diamond.
Proportion-scope It is an equipment or tool for assessing, measuring and demonstrating the proportions of diamonds either individually or comparing them with ideal.
Purity Purity is also known as clarity which describes the absence or presence of flaws inside or on the surface of a diamond. Diamonds are graded on a scale from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (eye visible inclusions or blemishes). If other factors are equal, flawless stones are most valuable.
Purple An exceptional and attractive fancy diamond color.
Radiant Cut The Radiant Cut is a fancy shaped rectangular or square diamond with cut corners. This shape comes with 62 to 70 facets and offers the elegance of the emerald shape with the brilliance of the princess shape. Trimmed corners are the signature of this shape, and they help to make the radiant cut a popular and versatile choice for jewelry.
Ratio The term ratio is also known as length to width ratio which is a comparison of the length and width of the girdle outline on fancy shaped diamonds. It is used to analyze the outline of fancy shapes only and it is never applied to round diamonds. The ratio is found by dividing the length of the diamond by the width where diamond width is always stated as 1. This ratio is simply a matter of personal aesthetic preferences and there is no defined ideal ratio for any of the fancy shaped diamonds.
Red Diamond One of the rare most and very desirable colors for diamond.
Reflection The term reflection is used for important optical effect where light bounces or returns once it strikes the surface of a diamond.
Refraction The term Refraction is also used for optical effect where light deviates or change its direction once it enters in a diamond.
Refractive
Index (RI)
When light meets the surface of a polished diamond, some of the light is reflected, whereas most is absorbed. This entered light in the diamond slows down and is bent from its original path due to the difference of density between air and stone. This process is known as refraction. This refraction varies from gem to gem depending on density and can be measured and used to help identify the gem type. This measurement is known as refractive index (RI).
Refractometer Refractometer is a device that is used to measure the refractive index of gemstones including diamonds.
Rough The term rough is used for any uncut or unpolished diamond.
Rough Girdle A grainy, pitted or uneven girdle surface, often with nicks.
Round Brilliant cut The round brilliant cut diamond is the most traditional and popular of all the diamond shapes. This cut is considered as ideal for a diamond because it maximizes a stone’s sparkle. It has 58 facets which offer great brilliance and stability. These 58 facets include 1 table, 8 bezel facets, 8 star facets, 16 upper-girdle facets on the crown, 8 pavilion facets, 16 lower-girdle facets, and usually a culet on the pavilion, or at bottom. This shape of diamond is most commonly used in solitaire diamond engagement rings.
Saturation A color’s position in a diamond on a neutral to vivid scale.
Scintillation This term refers to the display of sparkle or reflection from the polished facets of a diamond visible when the observer is in motion.
Scratch Scratch is a narrow, shallow, elongated nick on the surface of a diamond which usually appears as faint white lines, curved or straight, under magnification.
Secondary Deposit Minerals and/or gemstones that have been separated from their original host rock, usually due to effects of weather, and deposited elsewhere. An alluvial deposit is an example of a secondary deposit.
Semi Precious,Semi Precious Stone Stones those are valued for their beauty and not covered under any one of the four ‘Precious Stones’, Diamond, Emerald, Ruby or Sapphire, are known as semi precious stones. Semi precious stones are available in all price ranges from low priced to high priced. Semi precious stones are Alexandrite, Amethyst, Aquamarine, Citrine, Garnet, Iolite, Onyx, Opal, Pearl, Peridot, Tanzanite, Topaz, Tourmaline etc.
Semi-mount A style of jewelry setting that has the side stones already mounted, but which contains an empty set of prongs which are intended to mount a diamond center stone as per the customer’s choice.
Setter Setter is the person who puts diamonds or other gems into jewelry mounts.
Setting Setting is the process of fixing a diamond or other gem into a mount to create a piece of jewelry.
Shape A Diamond Cut by Shape describes the outline of the stone and pattern of the facet arrangement. Diamonds are available in various shapes like Modern Round Brilliant, Emerald, Princess, Heart, Oval, Pear etc. Round brilliant is the most popular shape for all jewelry items. All other non-round shapes are called fancy shapes.
Sieve A tool for sorting rough or polished diamonds by size. Diamond sieve sets have interchangeable sieve plates each drilled with different sizes holes.
Silver Silver has been known and used for thousands of years and it is considered as one of the three precious metals along with gold and platinum. Pure silver is very soft metal with its lustrous white color. Silver is used as jewelry metal well before the development of white gold alloys, and before platinum could be isolated.
Simulant,Simulated
Stones
Simulated stones can be anything that resembles a natural gemstone but does not have the same physical characteristics or chemical composition. These items are also known as imitation stones and usually much less expensive than the natural forms. Simulated stones are often made of glass or plastic and most can be detected easily by a jeweler.
Single Cut A very small round diamond with only 17 or 18 facets, instead of the normal 57 or 58 facets of a full cut round brilliant. These facets include 8 bezel, 8 pavilions, a table and sometimes a culet facet.
Slight Inclusions,
SI,SI1,SI2
Slightly Inclusion is clarity grade that refers slight inclusions in a diamond which are easily visible under 10X magnifications. It is graded as SI1 and SI2.
Solitaire A ring or any other piece of jewelry containing a single diamond or other gem. This style is very popular in rings.
Sort, Sorting Usually this term is used to classify rough diamonds into groups depending on their size, color, surrounding material where as in case of polished diamonds it is used classify into grades depending on size, color, clarity.
Spread Stone A Diamond which has been cut with a large table and a thin crown, to retain greater weight. In other words, a diamond which is cut too shallow.
Star Facet The eight triangular facets that surround the table facet of a round, brilliant-cut diamond. It is named star facets because they from an eight pointed star when viewed from above.
Step Cut Step cut is a style of faceting arrangements which is named because of its broad, flat planes that resemble stair steps. In this style of arrangement, there are three concentric rows of facets arranged around the table and, on the pavilion, there are three concentric rows arranged around the culet.
Stone A general word for any gemstone including diamond.
Surface Graining Surface graining is an indication of structural irregularity in a diamond. Usually parallel lines are visible on the surface or facet edges which look similar to grain in wood. These grain lines reflect due to imperfect polishing.
Symmetry Symmetry is an important aspect of the diamond cutting process which refers to the balance of the outline shape and alignment of the facets. It is graded as Ideal, Excellent, Very Good, Good, Fair or Poor.
Synthetic A synthetic diamond shares a natural stone’s physical, chemical and optical qualities, but it is created in a laboratory. Some modern synthetic diamonds look more natural and are more difficult to identify, but an experienced jeweler or gemologist can usually detect them.
Table Table is the largest and flat facet which is placed on top of a diamond. Most of the light enters and exits from this part of a diamond.
Table Percentage The table percentage is a comparison of the diameter of the table facet to the diameter of the entire diamond.
Tension Setting A method of setting diamonds and other gems using only the springiness of the mount to hold the stone firm. Although it look quite spectacular but very unsafe and it should be avoided.
Tiffany The Tiffany, the best of ever found yellow diamonds, weighs 128.51 carats and cut as cushion-shaped brilliant with 90 facets.
Tone An attribute of color which determines its lightness or darkness of shading and important in grading fancy colored diamonds.
Transparent, Transparency Ideally, a diamond should be completely transparent and any opacity is undesirable.
Treated Diamond,
Treatment
Treated diamonds are those which have been processed in some way to enhance their color or clarity. A number of treatment techniques are used to improve the color and appearance of natural and synthetic diamonds. Heat treatment is the oldest method whereas other techniques include bleaching, dying, laser drilling, fracture filling, high pressure high temperature (HPHT), annealing, irradiation, and surface coloration.
Trigon Trigon refers to very small triangular marks usually on surfaces of rough and polished diamonds, due to twinning and other crystal growth factors.
Trilliant Cut,Trillion
Cut
The Trilliant Cut is a triangular fancy shaped diamond which is also known as Trillion Cut. This shape of diamond looks unusual and displays a very sharp brilliance or fire. It may either have pointed corners or more rounded corners.
Twinning Twinning refers to two or more mineral crystals that have grown together in a symmetrical nature and crystal growth direction of one crystal has changed or a negative crystal growth has taken place.
Ultrasonic Cleaner Ultrasonic Cleaner is a tool, generally used by jewelers, to clean jewelry effectively. The ultrasonic vibrations help to free most types of dirt, grime, and oils from these jewelry items. Some ultrasonic cleaners come with a heating unit also.
Ultraviolet light Ultraviolet light consist short wavelengths in comparison of visible light’s wavelengths and due to this it is invisible to naked eye. Ultraviolet light is in between visible light and X-rays.
Upper Girdle Facet Upper Girdle Facet is any of the sixteen facets on the crown, adjoining the girdle of a diamond.
Vivid The term vivid is used for color grading of fancy colored diamonds to denote the most intensely colored stones.
Very Slight
Inclusions,
VS, VS1, VS2
It is a clarity grade that refers minor or slight inclusions in a diamond which are difficult to see under 10X magnifications. It is graded as VS1 and VS2.
Very Very Slight
Inclusions,
VVS, VVS1, VVS2
It is a clarity grade that refers tiny or very slight inclusions in a diamond which are extremely difficult to find, even under 10X magnifications. It is graded as VVS1 and VVS2.
White Diamond White diamonds are transparent or colorless and promoted as the best, but only because other attractive colors are extremely rare.
Wisp Wisp refers to a type of inclusion which occurs due to twinning or in other words it is an irregularity in the crystal growth.
X-Ray,X-Rays X-rays are used to sort rough diamonds as most diamonds fluoresce when exposed to these rays.
YAG YAG stands for Yttrium Aluminum Garnet which is used as a simulant, so an imitation for a natural diamond.
Yellow Diamond Generally most diamonds contain nitrogen which gives them a slight yellow tinge. But diamonds with more intense yellow hue are considered as fancy colored diamonds which make them rare and valuable.
Zirconium, Zirconia Zirconium (cubic zirconium) or CZ is a widely used simulant, an imitation for a natural diamond. Although it is easily detectable by it’s 80% higher weight than a diamond of the same proportions or by thermal conductivity testing.