Abraded Facet Edge
Archaic Greek word from which the word ‘diamond’ is derived. Adamas means ‘indestructible’.
Diamond cut or shaped into a square with the corners cut off, with rows or steps of elongated facets running parallel to the girdle on both the crown and the pavilion. It is similar to an emerald cut, but squared instead of rectangular, and has a pointed culet.
Bearding refers to tiny, hairline cracks along the girdle of a diamond that look like whiskers penetrating into it; the girdle can then appear to have a “fuzzy” outline. Bearding can affect both the clarity grade and the polish grade of a diamond.
A very dark, opaque diamond which appears black. Black diamonds are heavily included with graphite, blocking all or almost all transmission of light.
A blemish is a flaw on the exterior of a diamond, such as a scratch, abrasion, nick or chip. Blemishes are plotted (drawn) in “green” on the plotting diagram of a diamond certificate. Blemishes affect the polish grade of a diamond.
Diamonds that originate from areas controlled by rebel forces that are opposed to the governments in power, and are used to finance wars against these governments along with other resources like oil and timber. The Kimberley Process has been put in place to combat trade in blood diamonds, also known as 'conflict diamonds'. Click here to learn more about conflict diamonds and the Kimberley Process.
A coloured diamond with a natural blue body colour. Blue must be the predominant colour, but it may be modified by shades of grey, purple, or green. The colour in natural blue diamonds is created by the carbon-boron when the diamond is forming. Natural blue diamonds are extremely rare; some blue coloured diamonds with sufficient saturation fall into the valuable fancy blue colour category of diamonds.
The bow tie effect is a dark shadow across the center of a fancy shape diamond, in the shape of a man’s bow tie. This may be a sign of a poorly cut diamond - it is normally seen in diamonds that are cut too flat, too deep, or with badly arranged pavilion facets.
A small folded envelope-like paper used to safely hold a diamond. Information about the diamond is generally written or printed on the outside of the briefca.
The amount and intensity of light reflected to the eye through the surface of a diamond. Brilliance is a very important factor in creating beauty and life in a diamond. The proportions of the diamond are most important for light return, but all aspects of the four c’s contribute to creating brilliance.
A style of diamond cut, using triangular or kite shaped facets that radiate out from the center of the diamond to the girdle. The standard round brilliant cut consists of 32 facets plus a table above the girdle and 24 facets plus a culet below the girdle. Other shapes besides round can be faceted as brilliant cuts, including marquise cut, oval cut, pear cut, heart cut, and radiant cut diamonds.
Diamond cut or shaped into a full tear-drop with a circular cross section; briolettes are generally covered with triangular facets.
A blemish on the surface of a diamond that looks like an oily or frosted area. When a diamond is polished too quickly, heat from excessive friction builds up and leaves a mark on the surface. Burn marks affect the polish grade of a diamond.
Calf’s Head Diamond
Diamond cut or shaped to look like a triangle with all three corners cut off, similar in outline to the head of a calf.
Term used to describe an intensely or vividly bright-yellow fancy colour diamond.
Cape Series Diamonds
A broad scale of diamond colour grades that ranges from a near colourless, almost undetectable pale yellow to increasingly tinted yellow. Once it has enough yellow saturation to qualify as a fancy colour, it is no longer called a Cape Series diamond.
The standard unit of measuring the weight of a diamond. The origin of the word traces back to ancient times when diamonds were weighed on balances against carob beans, which held a consistent weight. One carob bean, or carat, weighs 1/5 of a gram.
Diamonds are made of pure carbon that has been subjected to and crystallised under enormous heat and pressure. Without the pressure, graphite is formed instead of diamond. Other forms of carbon can be found in substances like coal, but these are impure forms of carbon.
Small black graphite inclusions in a diamond. Diamonds are made of pure carbon that has been subjected to and crystallised under enormous heat and pressure. At times, not all of the carbon crystalises, and small black spots may remain.
Type of diamond inclusion that appears as an opening or large indentation on the surface of a diamond. A tiny version of a cavity is a called a pit. Cavities affect both the clarity grade and the polish grade of a diamond.
A complete, accurate report describing the specific characteristics of a diamond, issued by a recognised and independent diamond grading laboratory. A diamond certificate lists all the characteristics of a diamond that allows you to determine its current appraisal and fair market value. Also called a Diamond Grading Report. A diamond certificate is not an appraisal and does not contain a monetary value. Click here for a guide to the information that a diamond certificate must have.
A very rare type of diamond that changes colour when exposed to different light and heat conditions.
Type of inclusion that appears as a slight break out of the edge of a diamond, larger than a nick. Chips are caused when a diamond receives a sharp knock or blow; they affect both the polish and clarity grade of a diamond.
The World Jewellery Confederation, an international confederation of national jewellery trade organizations. CIBJO's purpose is to encourage harmonisation, promote international cooperation in the jewellery industry, and to consider issues that concern the trade worldwide. Foremost among these is to protect consumer confidence in the industry.
Term used to describe the relative presence or absence of inclusions in a diamond. Most diamonds, when formed, contain imperfections of one kind or another. Clarity, sometimes called purity, is one of the four c’s of diamond grading that determines the overall diamond quality and value.
Any artificial treatment or process meant to improve the appearance of a diamond’s clarity. Laser drilling and fracture filling are examples of diamond clarity enhancement. Click here to learn more about diamond clarity enhancements.
Cluster of pinpoint inclusions creating a hazy or milky area in a diamond. A diamond cloud can range from extremely sparse and faint, to dense and heavy. Clouds may also be small and localised, or spread throughout an entire diamond and affect the transparency.
Coated Diamond or Coating
Deceptive practice where a diamond is partially or wholly ‘painted’ with a colouring agent, either to hide unattractive colour, or to enhance desirable colour. To learn more about coated diamonds and diamond treatments, click here.
Cold Laser Inscription
The use of a very fine, precise laser beam to write a grading report number or customised personal message on the girdle of a diamond, generally for identification purposes. Cold laser inscription is 100% safe for diamonds, compared to hot laser inscription. The laser inscription is invisible to the naked eye and can only be seen with a magnifying loupe. Click here to learn more about diamond laser inscription.
Any diamond with a noticeable body colour other than white. Colour in diamonds is caused by either various impurities trapped in the diamond crystal as it was forming in the earth, or by irregularities in the crystal structure itself. Some coloured diamonds fall into the valuable fancy colour category of diamonds.
Diamonds that originate from areas controlled by rebel forces that are opposed to the governments in power, and are used to finance wars against these governments. Along with the other resources like oil and timber The Kimberley Process has been put in place to combat trade these diamonds, also known as'blood diamonds'. Click here to learn more about conflict diamonds and the Kimberley Process.
Upper part, or ‘top half’ of the diamond, above the girdle.
Crown Height Percentage
Type of inclusion where a mineral deposit, or sometimes another diamond, is trapped inside the diamond. Crystals often look like bubbles of various shapes and sizes.
Colourless, transparent, man-made material that is often used to imitate diamond - a diamond simulant. The chemical name is zirconinum dioxide (ZrO2).
Tiny point on the bottom of a brilliant cut diamond, or the bottom edge of a step cut diamond. A culet can be prone to damage, thus diamonds are usually set in jewellery in such a way that the culet is protected.
Can refer to any or all of the following: proportions, polish, symmetry, and/or shape and style of cutting (brilliant cut or step cut). The overall cut grade is one of the four c’s of diamond grading that determines the overall diamond quality and value.
Qualitative description of the overall make of the diamond, taking into consideration the proportions, polish, and symmetry. Cut is one of the four c’s of diamond grading that determines the overall diamond quality and value.
A diamond that is fashioned so as to minimise the amount of rough diamond crystal cut away. Carat weight may be gained, but brilliance, fire, and beauty are lost. The resulting proportions can make some diamonds look ‘bulgy,’ 'lumpy', ‘deep,’ or ‘undersize,’ while others may be flat or have symmetry deviations.
Diameter is a reference measurement against which most of the proportions on a diamond are calculated. On a round brilliant cut diamond, this is the length in milimeters of a straight line going through the center of a diamond. Click here to learn which standard diameter measurements correspond to specific well-proportioned carat weights. On a fancy shaped diamond, this is the average measurement in milimeters of the length and width.
Mineral composed almost exclusively of crystallised carbon. Carbon, when subjected to extremely high temperature and pressure, changes form and crystallises into diamond. Only approximately 20% of natural mined diamonds are of gem quality; the remaining 80% are industrial grade diamonds.
Organisation of diamond industry members. The main purpose of a diamond bourse is to provide an environment for the trading of diamonds within a set of ethical business practices. All diamond bourses have a legal, ethical framework to enact regulations for members and protect consumer confidence. Also referred to as a ‘Diamond Club’.
Diamond Dealers Club of South Africa
Diamond bourse, or organisation of diamond industry members. The main purpose of the DDCSA is to provide an environment for the trading of diamonds within a set of trading practices. The DDCSA has a legal, ethical framework to enact regulations for members and protect consumer confidence.
Minute particles of diamond, usually used as a high-quality abrasive for diamond polishing or industrial grinding, sawing, and filing.
Tool used to manually measure the dimensions of a diamond.
The bonds between carbon atoms that make up a diamond are stronger in some planes than others; this means that diamonds are marginally harder at some angles than at others. Diamonds thus have certain planes of weakness along which they can fracture, split or break. Directional hardness is related to the toughness and durability of diamonds.
Visible play of colours created by the break-up of light in a diamond. When light enters a diamond, it refracts then reflects off of the pavilion facets and separates into a rainbow of colours as it shines out of the crown facets. Also known as fire.
Diamond cut or shaped in an old-style cut with only sixteen facets plus the table - eight on the crown and eight on the pavilion. This simple diamond cut is still used at times today for extremely small diamonds. Also known as a 'single-cut' diamond.
Equivalent Colour Grade (ECG)
Occasionally ‘colourless’, or cape series diamonds will have a tint of brown or grey that is not visible face-up. These diamonds are graded on the same scale of color saturation as cape series diamonds, but are graded ‘ECG’ for hue. Diamonds with ECG grading are of lower value than those with no hue. Click here to see where to find hue on a diamond Certificate.
Facets added or remaining on a polished diamond in excess of the number usually found on a particular cutting style. Extra facets are added to remove surface imperfections, and inclusions located near the surface, without losing sizeable carat weight. Extra facets affect the polish grade of a diamond.
Any one of the flat, polished surfaces on a diamond.
Any positive diamond colour other than white, brown, or grey with a significant level of saturation. Natural fancy colour in diamonds is rare and valuable; the colour is caused by either impurities or structural abnormalities. Three factors to consider when grading a coloured diamond are body colour, tone, and saturation. Examples of fancy colours, or 'fancies': yellow diamonds, orange diamonds, pink diamonds, red diamonds, blue diamonds, purple diamonds, and green diamonds. Examples of non-fancy colours are grey and brown.
Diamond cut into any shape other than a round brilliant cut. Some examples of fancy shape diamonds are: princess cut, emerald cut, oval cut, marquise cut, heart cut, pear cut, and asscher cut diamonds.
Type of cleavage inclusion in a diamond with a wispy, feather-like appearance; the feather-like part extends from the origin of the break. Feathers occur along a cleavage plane, or plane of weakness, in a diamond due to directional hardness; they may appear transparent if viewed head on, or bright white if viewed at a 90° angle.
Visible play of colours created by the break-up of light in a diamond. When light enters a diamond, it reflects off of the pavilion facets and refracts, or bends, into a rainbow of colours as it leaves the crown facets. Also known as dispersion.
Unattractive donut-shaped white ring seen under the table of a round brilliant cut diamond with too shallow a pavilion depth. The ring is caused by the reflection of the diamond’s girdle. Diamonds with a fisheye lack brilliance, and show little life.
Bright, vivid streak of colour found in the glass-like resin filling of diamonds treated by fracture filling.
Trade term used to describe a diamond with a very shallow crown height and/ or pavilion depth. Flat round brilliant cut diamonds with a shallow pavilion tend to show a fish eye. Flat diamonds lack some brilliance and life.
Natural characteristic which causes many diamonds to glow under ultra violet light (UV), which is abundant in natural daylight and some artificial lighting. Fluorescence is caused by sub-microscopic structures within the diamond. Diamonds can have various colours of fluorescence, with blue being the most common.
Four fundamental criteria on which the quality and value of a diamond are judged: cut, colour, clarity, and carat weight. Two additional factors, transparency and the confidence in a diamond grading certificate are also important value factors. Click here to learn more about the C’s of diamond grading.
Type of break or crack inclusion in a diamond that is irregular, jagged and splintery. A fracture may not follow along a cleavage plane as does a feather, but spreads across the diamond in any other direction.
Treatment to enhance the apparent clarity of a diamond, whereby a glass-like resin is injected into feathers or fractures that reach the surface of the diamond. Feathers are visible when light reflects off of them; by filling them with a resin, light is able to travel through the feather, making it less visible. The resin causes what is known as a flash effect in the treated diamond. Fracture filling is not a stable diamond treatment and is easily altered with heat; click here to learn more.
The science, art, and profession of identifying and evaluating of all gemstones, including diamonds.
The outermost edge or rim of a diamond that outlines its shape. It is the circumference or perimeter that appears to divide the crown from the pavilion. A girdle may be faceted, polished, or bruted. The purpose of the girdle is to protect the diamond from damage such as chips.
A complete, accurate report describing the specific characteristics of a diamond, issued by a recognised and independent diamond grading laboratory. A diamond grading report lists all the characteristics of a diamond that allows you to determine its current appraisal and fair market value. Also called a Diamond Certificate. A diamond grading report is not an appraisal and does not contain a monetary value. Click here for a guide to the information that a diamond grading report must have.
Term used to describe a diamond weighing approximately 0.25 of a carat. In ancient times, 1.00 carat was equal to about four grains of rice. A “four grainer” would thus be referring to a diamond weighing approximately 1.00 carat (4 x 0.25=1.00).
Faint wavy, hazy, oily, or distorted transparent and sometimes shadowlike lines, either inside the diamond or on the surface of a diamond. Graining is caused by irregular growth and crystallization that takes place when the diamond is formed. Also known as “growth lines.”
A diamond with a natural green body colour. Green must be the predominant colour, but it may be modified by shades of yellow or blue. The colour in natural green diamonds is created by exposure to natural irradiation in the earth that produces structural defects; natural green diamonds are extremely rare. Some green coloured diamonds with sufficient saturation fall into the valuable fancy green colour category of diamonds.
Measure of resistance to scratching and abrasion. Diamond is the hardest material on earth, a 10 on Moh’s Scale; however, it is not the toughest. Hardness and toughness together determine the durability of diamond.
Diamond cut or shaped into a heart, with a cleft in the wide end, and a softly tapered point at the narrow end.
Hearts & Arrows
Describes a pattern that appears in some round brilliant cut and square cushion cut diamonds that have a certain parallelism and symmetry. When viewed from above through the crown, the pattern is a series of eight arrowheads. From below through the pavilion, the pattern appears as eight heart shapes. Hearts & arrows does not mean that a diamond is ideal cut, only that it is symmetrical.
Hot Laser Inscription
The use of a laser beam to write a number or customised personal message on the girdle of a diamond, generally for identification purposes. Hot laser machines operate at a higher wavelength, and unlike cold laser inscription can penetrate into and thus damage the diamond; penetration can result in chips and fractures. Click here to learn more about diamond laser inscription.
HPHT (High Pressure High Temperature) Treatment
Treatment to change or artificially enhance the colour of a diamond. Certain types of diamonds are subjected to extreme heat and pressure conditions in a laboratory, which rearranges their atomic structure and thus alters their colour. Click here to learn more about HPHT treated diamonds.
Occasionally ‘colourless’, or Cape Series diamonds will have a visible negative tint of brown or grey. These diamonds are graded on the same scale of color saturation as Cape Series diamonds, but will state the hue on the certificate. Diamonds with brown, grey, or ECG hue are of lower value than those with no hue. Click here to see where to find hue on a Diamond Certificate.
Term often used for a round brilliant cut diamond that is believed to be excellent across the board for proportions and overall make. There are many different 'ideal cuts', the most famous being the Tolkowsky Ideal Cut. The range for ideal cut diamond parameters can often be very broad, so care must be excercised in labeling a diamond as 'ideal cut'.
Internal imperfections of a diamond affecting the clarity grade. Diamonds grow deep in the earth under extreme pressure and temperature; under these conditions, it is rare to find a diamond that is internally flawless.
The original skin of the rough diamond that remains after polishing and is indented into the body of a diamond, not confined to its surface. An indented natural can affect both the polish grade and the clarity grade of a diamond.
Diamond grading laboratory that has no financial interest in the actual trade (buying and selling) of diamonds.
Industrial Grade Diamond
Diamond usually not polished as a gemstone, as it does not meet the minimum quality criteria for grading. Industrial diamonds are very heavily included, lacking the transparency, brilliance and life that a gem quality diamond must exhibit. Industrial diamonds are somtimes used in their rough diamond form in jewellery. Industrial diamonds are very useful for tools, drills, lasers, abrasives, and other such uses. Only approximately 20% of mined diamonds are of gem quality.
Internal Laser Drilling
Treatment to enhance the apparent clarity of a diamond by reducing the visibility of dark inclusions. A precise laser beam is focused on a small dark inclusion - the black in the inclusion dissipates from the laser beam itself. Click here to learn more about laser drilling and clarity enhancement.
International Diamond Council
International organisation founded by the World Federation of Diamond Bourses (WFDB)and the International Diamond Manufacturers Association (IDMA) to establish standard rules for diamond grading and nomenclature.
International Diamond Manufacturers Association
International diamond trade association committed to fostering and promoting the highest ideals of honesty and best practice principles throughout the diamond industry worldwide.
Internationally Recognised Standards
Diamond grading rules and processes that are regulated and recognised by internationally accredited bodies. Examples of these bodies are CIBJO, LMHC, World Federation of Diamond Bourses, and the International Diamond Council.
Treatment to change or artificially enhance the colour of a diamond. Irradiated diamonds are bombarded with a variety of high-energy particles that physically alter their atomic structure, thus changing their colour. Most irradiated diamonds are annealed to further modify their colour. Click here to learn more about irradiated diamonds.
Jewellers Association of Australia
Association of jewellers that represents and promotes the interests of retailers, manufacturers, wholesalers, suppliers, importers, exporters, watchmakers and valuers involved in the jewellery and gemstone industry in Australia.
International certification program designed to follow a diamond from it’s origin as a rough diamond straight through to the finished product; its purpose is to ensure that diamonds come from sources which are free of conflict, unlike blood diamond, and are not traded to fund wars and violence. Click here to learn more about the Kimberley Process.
Blue-coloured rock from which most diamonds are mined, usually found in a kimberlite pipe or fissure.
Treatment to enhance the apparent clarity of a diamond by reducing the visibility of dark inclusions. A precise laser beam drills a small tunnel from the surface of the diamond to the dark inclusion; the black in the inclusion either dissipates from the laser beam itself, or else it is bleached out with acid. Click here to learn more about laser drilling and clarity enhancement.
Diamond that is not mounted in jewellery. Diamond certification is not possible when the diamond is set in jewellery, as none of the four c’s can be accurately assessed - only estimates are achievable.
Hand held magnifying lens. Diamond clarity must be graded with a 10x loupe that is corrected for spherical and chromatic aberration.
Diamond cut or shaped into an oval with pointed ends. Also called a ‘navette,’ which is the French word for “little boat,” as the shape is similar to that of a boat’s hull.
Set of certified and registered diamonds, with known colours against which other diamonds are compared to establish their colour. A diamond master set is neccesary for accurate colour grading. A first generation diamond master set is available to any diamond merchant or jeweller.
Cloudy or hazy diamond with reduced transparency, brilliance, and overall life. A milky diamond can result from numerous factors, for example a dense cloud or extremely strong fluorescence. Click here to learn more about transparency.
Scale from for classifying the relative hardness used for gemstones, based on the ability of harder gemstones to scratch softer ones. Moh's scale ranges from 1 to 10, with 10 being the hardest. Diamonds are the only material on earth to rate as a 10.
Near-colourless, slightly oily looking man-made material that is often used to imitate diamond - a diamond simulant.
Unattractive black shadow under the center of a round brilliant cut diamond that has too deep of a pavilion. The shadow is caused by the reflection of the table. Diamonds with a nailhead look dark, lacking brilliance and life.
National Diamond Colour Master Set
Set of certified and registered diamonds, with known colours from which other master sets may be derived.
Part of the original “skin” of a rough diamond that has been left on the polished diamond. Naturals affect the polish grade of a diamond, but do not have a significant impact if confined to the girdle area where they are usually located.
Type of diamond blemish that that appears as a tiny break out of the edge of a diamond, not large enough to be a called a chip and usually confined to the girdle. Nicks affect the polish grade of a diamond.
Old Mine Cut
Refers to a diamond that glows (fluoresces) strong blue under long wave ultraviolet light; in the past the term was used misleadingly to imply a diamond with superior colour. In fact, some diamonds with a high colour grade that have very strong fluorescence can look oily or milky under daylight.
Pavilion Depth Percentage
Pavilion depth expressed as a percentage of the diameter. Pavilion depth is an extremely important proportion to the brilliance of a diamond; diamonds with a pavilion that is too deep will have a nailhead, while diamonds with a pavilion that is too shallow or flat will have a fish eye.
Pavilion Main Facets
Diamond cut or shaped into the outline of a tear-drop or a pear, with a rounded head tapering to a point.
A coloured diamond with a natural pink body colour. Pink must be the predominant colour, but it may be modified by shades of purple, orange, and yellow. The colour in natural pink diamonds is created by irregular crystal structure. Some pink coloured diamonds with sufficient saturation fall into the valuable fancy pink colour category of diamonds.
Very tiny diamond crystal inclusions that are too small in size to distinguish their individual shapes. One pinpoint looks like a small “dot” under 10x magnification. Clusters of pinpoints create a cloud.
Plotting Diagram or “Plot”
Term for one hundredth of a carat. For example, a fifteen-point diamond weighs 0.15 carats. It could also be called a fifteen “pointer”.
Qualitative analysis of the overall surface condition of a diamond. The quality of polish is determined by the care put in by a polisher when finishing a diamond, and is important to the brilliance and scintillation given off by a diamond.
Lines left on the surface of the diamond which are visible under magnification, normally removed during the final diamond polishing process. Polish lines can affect the polish grade of the diamond.
Describes the girdle of a diamond that has been fully polished smooth and clear around the entire perimeter. Step cut diamonds such as emerald cut and baguette cut diamonds usually have a polished girdle, and some brilliant cut diamonds may have polished girdles as well.
Qualitative analysis of the overall proportions on a round brilliant cut diamond. Fancy shaped diamonds are not proportion graded; unlike round cut diamonds, there is no defined range of proportion standards for fancy shapes.
Relations between the dimensions and angles of a finished diamond. Examples of specific proportions are table size, depth percentage, and crown angle. Proportions are extremely important to the beauty, brilliance, and life in a diamond. Click here to learn more about proportions on a diamond grading report.
Diamond cut or shaped into a square or rectangular princess cut, with the corners cut off.
A coloured diamond with a natural red body colour. Red must be the predominant colour, but it may be modified by shades of pink or purple. The colour in natural red diamonds is created by irregular crystal structure. Natural red diamonds are the most rare of all diamonds. Some red coloured diamonds with sufficient saturation fall into the valuable fancy red colour category of diamonds.
Diamond in its natural state, exactly as it is found in the earth, prior to undergoing cutting, polishing, or alteration of any kind.
Round Brilliant Cut
Diamond cut or shaped into a circular outline or circumference, with a cone-shaped pavilion. The standard round brilliant diamond has 57 or 58 facets, and is the most popular style of cutting.
Sparkle of a diamond as light reflects off of its surface when it is moving, seen as quickly shifting flashes of light. The amount and intensity of sparkle depends on the quality of polish, as well as the size, shape, and symmetrical arrangement of facets.
Plastic covering that provides a safeguard against loose diamonds being lost or damaged. Laboratory sealing has a number of security features including electrostatic security bars, pressure-sensitive transparent adhesive and cryptoprint text which only becomes visible after opening the seal.
Diamond cut or shaped in an old-style cut with only 16 facets- 8 on the crown and 8 on the pavilion. This simple diamond cut is still used at times today for extremely small diamonds. Also known as an eight cut.
Degree and regularity in shape and placement of facets, how well they align and relate to each other. Symmetry is very important to the life in a diamond, especially the brilliance; it affects how light is reflected and refracted in a diamond. Symmetrical round brilliant cut diamonds often display hearts & arrows.
Man-made versions of the diamonds found in the earth. Synthetic diamonds have the same chemical structure and properties as natural diamonds, but are created in a laboratory in only a few days, instead of in the earth over billions of years - they sell at a much lower price. Click here to learn more about synthetic diamonds.
Tapered Baguette Cut
Diamond cut or shaped into a triangle with one corner cut off, and rows or steps of elongated facets running parallel to the girdle on both the crown and the pavilion. It is a modified version of a standard baguette cut.
Degree or depth of colour in terms of lightness or darkness. The tone of a coloured diamond can range from very pale to very dark; it is the degree to which the colour of a diamond approaches white on the pale end, and black on the dark end.
Measure of brittleness, or resistance to fracture and breaking. Diamond has very good durability, but due to its directional hardness diamonds have certain planes of weakness along which they can split or break. Toughness and hardness together determine the durability of diamond.
Degree to which a diamond transmits light, directly relevant to the cloudiness or haziness of the actual diamond material, and the quality of the crystal. Click here to learn more about transparency and the DCLA Transparency Grading System.
Diamonds that are artificially enhanced, to improve either colour or clarity. These treatments fundamentally alter the diamond from its natural state, and therefore need to be fully disclosed. Click here to learn more about treated diamonds.
Triangular shaped natural, with very fine triangular concentric lines. Trigons, when present, are a definitive indicator of natural diamonds.
Diamond cut or shaped into a triangle, sometimes with curved sides.
Type of diamond inclusion that appears as a line or ribbon of pinpoints, tiny feathers, clouds, and crystals. Twinning lines are created where two rough diamonds have grown together in the earth under extreme heat and pressure.
World Federation of Diamond Bourses
International confederation of diamond bourses. The WFDB imposes strict rules and guidelines for ethical and professional conduct for the diamond trade on an international level.
A coloured diamond with a natural yellow body colour. Yellow must be the predominant colour, but it may be modified by shades of green, orange, or brown. The colour in natural yellow diamonds is created by the presence of nitrogen as an impurity when the diamond is growing. Natural yellow diamonds are common; canary diamonds are however more rare.
The diamond trading floor that gives all diamond buyers direct access to DCLA guaranteed diamonds from Australian diamond dealers.
Friday 22 August, 2014
GEM DIAMONDS REVENUE AT THREE YEAR HIGH
Gem Diamonds Ltd has had a 50 percent value increase this year. Rough diamond prices have risen about 14 percent year to date on Chinese demand.
Wednesday 6 August, 2014
GEM DIAMONDS RECOVERS 198 CT DIAMOND
Gem Diamonds recovered 198-carat the type IIa diamond at its Letseng mine at the end of July. The diamond a top white with no fluorescence will fetch an exceptional price when sold this later this year.
Monday 28 July, 2014
DIAMOND PRODUCTION UP BY 12% DE BEERS
Debswana in Botswana and De Beers Consolidated Mines in South Africa year to date production has increased by 12%.
Wednesday 16 July, 2014
FUNDING ZIMBABWE DIAMOND MINES RISKY
Rand Merchant Bank (RMB) a leading South African bank said diamond mining ventures in Zimbabwe are difficult to fund because of the high political risk and uncertainty in the country.
Monday 16 June, 2014
PETRA DIAMONDS DISCOVERS 122.5 CT BLUE DIAMOND
Petra Diamonds has found a 122.5 carat blue diamond at the Cullinan mine in South Africa.
This is the largest blue diamond found by Petra since the mine was sold to Petra by De Beers in 2008.
Monday 5 May, 2014
DCLA 13 YEARS OLD.
DCLA Australia's leading diamond grading laboratory has turned 13.
Thursday 3 April, 2014
DCLA SYNTHETIC DIAMOND IDENTIFICATION
DCLA Laboratory established in 2001 has always had the ability and equipment to identify synthetic diamonds.