This is a quick reference guide to help you understand common diamond and jewellery terminology.

Click on the letter links below to speed up your search:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A:

AGS: The American Gem Society was established in 1934. It is a recognised authority and association dedicated to setting and maintaining the highest possible standards of business ethics and professionalism in the jewellery industry.

AGSL: The American Gem Society Laboratories is recognized by the jewellery industry as one of the foremost authorities in diamond grading. Known industry-wide as the laboratory with the highest standards of evaluating diamond quality, the AGSL employs leading-edge research and technology on diamond grading, diamond cut grade research and the light performance of a diamond, all to benefit you in your diamond purchase.  An example of an AGSL report is: The Diamond Quality® Document (DQD).  It provides a complete diamond grading analysis of the 4Cs with special detail to cut including information about light performance, proportions, polish and symmetry.  All Ideal Cut diamonds come with a Diamond Quality® Document.
 

Alloy: Alloys are made by melting and mixing two or more metals. For example white gold is an alloy of gold and at least one white metal, usually nickel or palladium.

 
Anneal: Annealing is a heating enhancement process used to enhance the strength and colour of various coloured gemstones.

 
Appraisal: An appraisal is a written statement giving an independent and expert opinion as to the worth or current value of your jewellery as well as an accurate description of it.  Insurance companies require a written appraisal/valuation to ensure adequate compensation or jewellery replacement in the event of a loss occurring.

 
Assay, Assaying: Testing carried out to determine that the fineness of precious metals conforms with the statement or claim of fineness that the maker has claimed (usually by stamping a number such as 750 for 18K gold) on the item.

 
Asscher Cut: The ‘Asscher Cut Diamond’ was developed in 1902 by the Asscher Brothers of Holland. It has a very unique cut pattern known as a stepped square cut. It is often called the ‘square emerald cut’ and like the emerald cut it has cropped corners. 

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B:

Baguette: A small four-sided step cut that is often set to accent a larger centre stone.  Baguettes can be rectangular, square or tapered (one narrow end and one broader end).

Bail: A component of certain types of jewellery, mostly necklaces, that is used to attach a pendant to a chain or cord. The bail is normally placed in the center of the necklace where the pendant hangs.

Band (Wedding): A ring to symbolize marriage which is exchanged during the wedding ceremony. It is traditionally made of a precious metal and has the same width all the way around. Wedding bands often include diamonds nowadays.

Bezel Facet: Also known as Kite Facet. A facet on the crown, or upper part of the diamond above the girdle. A round brilliant diamond has eight bezel facets.

Bezel Setting: A protective setting in which a metal rim surrounds the gemstone, securing it in place by the girdle.

Blemish: A clarity characteristic that is confined to the surface of a polished gemstone.

Bow-tie Effect: A dark spot in the shape of a bow-tie found in fancy shaped diamonds such as the Marquise, Oval, and Pear. This bow-tie effect usually runs horizontally, across the center of the diamond and appears in stones with poor proportions.

Brightness: The reflections of white light from the surface and interior of a diamond when viewed from above.

Brilliance: The brightness that is created by white light reflections from the surface and inside of a polished diamond.  Brilliance is maximised by cutting a diamond to the correct proportions.

Brilliant Cut: A specific gemstone that is cut with triangular or kite-shaped facets that radiate from the centre towards the girdle and that has exactly 58 facets (including the culet).  The most popular shape is the round brilliant cut however a brilliant cut can have several shapes including oval, radiant, pear or heart-shaped.

Brillianteering: The final stages of the diamond cutting process when the star facets and the upper and lower girdle facets are polished on a diamond.

Bruise: A diamond's internal characteristic consisting of a minor chip or concussion on the stone that may create root-like lines inside the diamond.  Bruises are found in diamonds of VVS1 and lower clarity grades.

Bruted Girdle: A girdle cut that gives the girdle a frostlike appearance.

Bruting: Forming the basic face-up outline of a diamond to prepare it for faceting.

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C:

Canary: Name given to a Fancy coloured yellow diamond with a vivid or intense colour.

Carat (ct): An international unit of metric measurement for gemstones where one carat equals 200 milligrams, or 0.200 grams. Each carat is divided into 100 points, so a 75 point stone is ¾ of 1 carat, a 50 point is ½ carat, etc.

Cavity: A diamond's internal characteristic consisting of a tiny opening in the stone.

Centre Stone: The central, main stone in a piece of jewellery set with smaller accent stones. In a ring set with one stone this is called a solitaire.

Certification: A diamond certificate is an official grading report for diamonds and gemstones created by a gemologist or gemstone laboratory. The diamond is examined under a microscope and other lab equipment to create a certificate with all the major quality factors (4 C's) and other characteristics.

Channel Setting: A setting style where uniform gemstones are mounted in a grooved channel touching each other. No metal is visible between the stones.

Clarity: Clarity is the degree to which a gemstone is free from inclusions and blemishes. A clarity scale has been designed to grade flaws in valuing gemstones. For diamonds, the clarity scale ranges from FL (flawless) where there are no internal or external flaws, to I3, with many imperfections clearly visible to the naked eye. The Diamond Shop mostly carries diamonds of SI2 clarity and above.

Clarity Characteristics: Inclusions and blemishes that help establish a gem's identity and quality.  They make every gemstone unique.

Clarity Plot:  A diagram that shows the approximate size, type and position of a diamond's inclusions when viewed under a microscope.

Claw Setting: A setting in which metal prongs or claws hold a gemstone in its setting.

Cloud: A diamond's internal characteristic consisting of a cluster of tiny crystals or pinpoints.

Colour: One of the 4 Cs, colour refers to a diamond's body colour on a colourless to light yellow scale. The colour grade is established by gemological laboratories who compare each stone to a master set of diamonds. For diamonds this scale starts with the letter D (colourless) down to Z (yellow-brown). For coloured stones, each type has its own grading system. Colour is one of the most important value factors for all gemstones.

Colourless: A term to describe diamonds in the colour range of D to F.

Comfort Fit: A term for a ring design where the inside edges are smoothed to a round surface for more comfortable wear.

Crown: Top part of a faceted gemstone above the girdle consisting of the table and crown facets below it.

Crown Angle: The angle formed by the bezel facets and the girdle plane.

Crown Height: The distance from the girdle to the table when viewed from the side.

Crown Height Percentage: Is calculated by dividing the actual height of the crown by the average girdle diameter.

Crystal: A diamond's internal characteristic consisting of a mineral deposit inside a diamond which can vary in shape, size and colour.

Culet: The small facet or point at the bottom of the pavillion of a finished gem.

Cushion: A diamond shape that is square or rectangular with rounded edges.

Cut: This refers to the proportions and finish of a gemstone and is one of the most important factors in determining the amount of brilliance a gemstone can produce. 

Cut Grade:  A combination of a round brilliant diamond's face-up appearance (brightness, fire and scintillation), design (weight ratio and durability) and craftsmanship (polish and symmetry) expressed as a GIA rating ranging from Excellent to Very Good, Good, Fair and Poor.  AGS grades diamonds as Ideal, Very Good, Good, Fair and Poor.

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D:

Depth: The height of a polished gemstone measured from the table to the culet.

Depth Percentage: The measurement of a gemstone's depth in relation to its diameter expressed as a percentage. This value determines the brilliance, fire and cut of a gemstone.

Diameter: The width of a diamond as measured through the girdle. The measurement is an estimated average.

Diamond: A mineral that is formed naturally when carbon is crystallised under intense heat and pressure beneath the earth's surface. Diamond is the hardest naturally occurring substance on earth (10 on Moh's scale), meaning that it is most resistant to scratching.

Diamond Dossier: A GIA report that offers the same grading information as the GIA Diamond Grading Report but without the plotted diagram. For added security a microscopic laser inscription of the report number on the diamond’s girdle can be included. The GIA Laboratory issues these reports for loose, natural diamonds between 0.15 and 1.99 carats, in the D-Z colour range.

Diamond Grading Report: A GIA Report of a diamond’s 4C’s – colour, clarity, cut, and carat weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. The GIA Laboratory issues these reports for loose, natural diamonds in the D-Z colour range that weigh 0.15 carats or more.

Dimensions: The measurements (size) of a gemstone.

Dispersion: The separation of white light into its spectral (rainbow) colours by refraction. Also known as 'fire.'

Durability: A gemstone's ability to withstand wear, heat and chemicals.

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E:

Emerald Cut: A diamond shape that is rectangular with diagonally cut corners. Also known as a step cut.

Excellent Cut: The Gemological Institute of America's highest Cut Grade for a round brilliant diamond. This means the diamond has Excellent performance, proportions, and finish to display maximum sparkle, fire and brilliance.

Extra Facet: A diamond that has an additional facet to the normal amount of facets of a particular cut.

Eye-clean: A gemstone where the flaws cannot be seen with the naked eye.

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F:

Facet: A flat, polished surface on a finished gemstone.

Fancy Colour: Fancy-coloured diamonds have a different colour grading scale which is exclusive of the D to Z grading scale associated with white diamonds. They come in a wide range of colours and are a lot more expensive than white diamonds.

Fancy Cut/Shape: Any gemstone shape that is not round.

Feather: A collective term for a diamond's cleavages and fractures.

Finish: The quality of a diamond's surface condition (polish), and the size, shape and placement of the facets, including the evenness of the outline (symmetry).

Fire: The flashes of coloured light reflected back into the eye from within a polished diamond. Generally, diamonds with a higher cut grade refract more colours when moved in the light.

Fluorescence: When exposed to long wave ultra-violet light, some diamonds will glow (display fluorescence). The amount of fluorescence will determine a diamond's value. Fluorescence is graded from None to Very Strong. Faint or moderate blue fluorescence does not usually affect a diamond's appearance, it can actually make lower coloured (yellowish) diamonds appear whiter in daylight. Very Strong fluorescence can give a diamond a slightly oily or cloudy surface appearance.

Four Cs: Four value factors (cut,colour, clarity and carat weight) that describe a finished diamond's quality.

Fracture: A type of inclusion (crack or feather) on the surface of a gemstone, it can appear as a whitish area because no light can pass through it.

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G:

GIA: The Gemological Institute of America is one of the world’s foremost authorities on grading diamonds, coloured stones, and pearls.

Girdle: The narrow rim around a gemstone where the crown and pavilion meet. The girdle measurements define the diameter of the stone.

Girdle Outline: The face-up shape of a polished gemstone.

Girdle Thickness: The thickness of a diamond's girdle measured on a scale from Thin to Extremely Thick. If the girdle is too thin the stone is susceptible to cracking or breaking; if it is too thick the stone will show less fire and brilliance.

Grading Report: A report created by a gem laboratory that describes your gemstone.

Graining: Internal clarity characteristic consisting of faint lines or streaks that show a diamond's irregular crystal growth.

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H:

Hardness: The resistance of a gemstone to scratches and abrasions.

Heart: A diamond shape that is in the form of a heart.

Hearts and Arrows: A term used to describe the visual effect achieved in a round brilliant diamond with perfect symmetry and angles. The Hearts and Arrows pattern is visible when viewed under special magnification. Eight symmetrical hearts can be seen from the bottom, and eight uniform arrows from the top.

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I:

Ideal Cut: The American Gem Society's highest Cut Grade for a round brilliant diamond. This means the diamond has Ideal performance, proportions, and finish to display maximum sparkle, fire and brilliance.

Inclusion: A clarity characteristic that is inside a gemstone or extends into the gemstone from its surface.

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K:

Karat (K/kt/ct): Is a measure of the purity of gold. Because pure gold (24K) is very soft it is not ideal for everyday jewellery wear. Alloys such as silver, copper, nickel, and zinc are added to it to give it strength, durability and colour. The most common karats used in jewellery making are:

• 22 karat (22K) gold contains 22 parts gold and 2 parts another metal or metals, making it 91.3% gold.
• 18 karat (18K) gold contains 18 parts gold and 6 parts another metal or metals, making it 75% gold. Often stamped on jewellery as 750.
• 14 karat (14K) gold contains 14 parts gold and 10 parts another metal or metals, making it 58.5% gold. Often stamped on jewellery as 585.
• 9 karat (9K) gold contains 9 parts gold and 15 parts another metal or metals, making it 37.5% gold. Often stamped on jewellery as 375.

Kite Facets: A kite-shaped facet on the crown, or upper part of the diamond that extends from the table to the girdle.  A round brilliant diamond has eight kite facets.

Knot: Internal clarity characteristic consisting of a diamond crystal that reaches the surface of a diamond facet.

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L:

Laser Inscription: A microscopic inscription on the girdle of a diamond to help with its identification. The inscription is often the diamond's certificate number, a logo, or a personalised message.  Not all diamonds are laser inscribed.

Length-to-Width Ratio: A comparison of the length to the width of fancy shaped diamonds. The ratio is found by dividing the length of the diamond by the width. Eg. A one carat marquise cut diamond that measures 10.07mm in length and 5.30mm in width has a length-to-width ratio of 1.9 or 1.9:1.0.

Light Performance: How a diamond looks when viewed from the top. The combination of brightness, fire, and scintillation that make a diamond beautiful. 

Loupe: A small magnifying lens used to examine gemstones and jewellery. Typical magnification is 10x.

Loupe Clean: A gemstone with no visible inclusions under 10x magnification.

Lower Girdle Facets: A facet on the pavilion, or lower part of the diamond just below the girdle. A round brilliant diamond has sixteen lower girdle facets.

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M:

Make: The qualities of a faceted diamond's proportions and finish.  An Ideal, Excellent, or Very Good make diamond will have proportions that maximize its fire and brilliance. These proportions, symmetry, and polish effect the beauty of a diamond much more than perfect colour or clarity.  A fair or poor cut diamond will have little sparkle.

Marquise: Marquise cut diamonds have an elongated boat-like shape with pointed ends.

Master Set: A set of polished diamonds of known body colour by which jewellers can compare and grade the colour of a particular diamond from D to Z.   Colour master sets also exist for describing the hues and saturation of coloured diamonds and gemstones.

Measurements: A diamond's dimensions indicated on a grading report/certificate.  For round diamonds: minimum diameter-maximum diameter x depth.  For fancy-shaped diamonds: length x width x depth.

Melee: Very small faceted diamonds.

Mixed Cut: A mixed cut is one in which the style of the facets above and below the girdle are different.  A standard mixed cut is brilliant cut above and step cut below.

Mohs Scale: A scale that determines the relative hardness of minerals.  Developed by Friedrich Mohs, the scale uses a scratch test and ranks minerals soft to hard from 1-10. A diamond has a hardness of 10.

Mounting: (Or setting) What holds a gemstone in place in a piece of jewellery.  Some mountings include prong (claw), bezel, channel, and pavé.

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N:

Natural: A blemish whereby a small part of the original rough diamond's surface remains unpolished on the surface of the final, polished diamond.

Near-colourless: A term to describe diamonds in the colour range of G to J.

Needle: Internal clarity characteristic consisting of a long, thin, light included crystal that looks like a tiny rod.

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O:

Off-centre Culet: A problem when cutting a gemstone that affects a stone's symmetry.

Oval: A diamond shape that is in the form of an oval.  Oval cut diamonds range in shape from nearly round to very elongated.

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P:

Pavé Setting: A setting style where many small gemstones are set low and very close together creating a 'paved' appearance. 

Pavilion: Bottom part of a faceted gemstone below the girdle consisting of the lower girdle and pavilion facets below it.

Pavilion Angle: The angle measured between the girdle plane and the pavilion main facets.

Pavilion Main Facets: The eight facets on the pavilion of a round brilliant diamond.

Pavilion Depth Percentage: The depth of the pavilion (from the girdle plane to the culet) expressed as a percentage of the average girdle diameter.

Pear: The pear cut, or teardrop shape, is a variation of the round brilliant cut diamond. A pear cut is really a hybrid of the round brilliant cut and marquise cut diamond.

Per Carat Price: The price of a gemstone divided by its weight.

Pinpoint: Internal clarity characteristic consisting of a very small included crystal inside the diamond that looks like a tiny dot or a group or string of dots under 10X magnification.

Piqué: A term used to describe included gemstones.

Platinum: A rare precious metal more durable than gold that is hypo-allergenic and tarnish resistant. It is very popular with engagement rings. True platinum jewellery should be stamped with 950 Plat or PLAT which is 95% pure with 5% alloys.

Plot:  A diagram showing a gemstone's significant clarity characteristics as a colour-keyed diagram.

Point: One hundreth (1/100) of a carat (0.01ct). Eg. 50 points = 0.50ct or a half carat.

Polish: The quality of a polished diamond's facet surfaces.

Precious Metal: Metals used to create fine jewellery which include gold, platinum, palladium and silver.  Titanium and stainless steel are also popular for men's jewellery.

Princess Cut: The princess cut diamond is traditionally square with 90 degree angled corners. Princess cut diamonds can also be rectangular in shape.

Prong Setting: A ring setting style popular in engagement rings. Metal prongs (claws) are bent around the girdle of the gemstone to hold it securely in place. This allows more light to enter the stone. This setting usually consists of four or six claws and is also used for pendants, earrings and bracelets.

Proportions: The angles and relative measurements of a polished gemstone and the relationships between them.

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R:

Radiant Cut: The radiant cut is usually rectangular in shape but also popular in square. It combines the brilliance and sparkle of a round diamond with the classic emerald cut shape.

Report: A document that describes a diamond's characteristics such as its dimensions, clarity, proportions, colour, finish, symmetry and carat weight. All diamonds purchased from The Diamond Shop website come with one of the following reports; a GIA Diamond Grading Report, a GIA Diamond Dossier®, or an AGSL Diamond Quality Document.

Rhodium: An alloy used to plate sterling silver and white gold. Its protective coating makes these white metals whiter and brighter, and also prevents tarnishing.

Ring setting: Collective term for the shank and the head of a ring before the centre stone has been set.

Ring Size: The diameter of a ring expressed as a letter from A to Z (in Australasia). The average ring finger size is M. American and International ring sizes are expressed as numbers.

Rose Gold: Also known as pink gold. It gets its pink colour due to a higher percentage of copper in the metal alloy.

Rough: An uncut diamond.

Round Brilliant: The round brilliant cut diamond is the classic diamond shape and most popular shape for diamond engagement rings. It exceeds all other shapes in exuding fire and brilliance.

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S:

Scintillation: The flashes of light seen when a diamond, the light or the observer moves.

Setting: (Or mounting) What holds a gemstone in place in a piece of jewellery.  Some settings include prong (claw), bezel, channel, and pavé.

Shank: The part of a ring that encircles the finger.

Shape: Refers to the outline of a polished diamond or gemstone when viewing it from above. Popular shapes include: round brilliant, princess (square), oval, radiant, pear, marquise, heart.

Shoulder: One of the two sides adjacent to the rounded end of a pear or oval shaped diamond.

Side Stone(s): A diamond or gemstone that accents a center stone in a jewellery setting.

Solitaire: A ring or pendant with a single diamond or gemstone and no side stones.

Sparkle: A term used to describe the fire, brilliance and scintillation that a diamond displays.

Spread: How big a diamond appears when viewed from above. This should not be confused with the actual carat weight of the diamond. Factors that affect spread are the table depth percentage, girdle thickness and crown and pavilion angles. An Ideal Cut diamond has an equal weight and spread.

Star Facets: A small triangular facet on the crown, or upper part of the diamond next to the table. A round brilliant diamond has eight star facets.

Step Cut: A type of diamond cut where the facets are four sided and run parallel to the girdle. E.g. Emerald cuts, or baguettes.

Symmetry: The uniformity of a gemstone's outline, and the shape, placement and alignment of its facets. Diamond symmetry is graded from Poor to Ideal. Poor symmetry is due to factors such as uneven facets, off-centre tables and inconsistent girdle thickness and will result in loss of light and sparkle.

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T:

Table: The largest facet on a gemstone. The table is on top of the crown and allows refracted light to escape, creating brilliance.

Table Percentage:  The width of the table divided by the average girdle diameter of a gemstone. The table percentage (size) is critical to making a gemstone sparkle. If the table percentage is too low or too high the gemstone will lack sparkle.

Tension: A tension setting is one in which a gemstone is held in place by pressure rather than prongs, a bezel or other mounting.

Titanium: A very strong, light, non-corrosive metal often used in men's wedding rings.

Total Depth Percentage:  The depth (from the table to the culet) divided by the average girdle diameter of a gemstone. The depth percentage is critical to maximizing the brilliance of a diamond. It determines a diamond's proportions and ultimately the quality and grade of a diamond's cut.

Total Diamond Weight (TDW): The combined carat weight of all the diamonds in a piece of jewellery that only contains diamonds.

Total Gem Weight: The combined carat weight of all the stones that make up a piece of jewellery of a variety of gems.

Toughness: A gemstone's resistance to breaking and chipping.

Trilliant (Trillion): A triangular shaped brilliant cut diamond with 44 facets that is often used for side stones in rings. 

Twinning Wisp: Internal clarity characteristic consisting of a flat or ripple-like cloudy area produced by crystal structure distortion.

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U:

Upper Girdle Facets: A facet on the crown, or upper part of the diamond just above the girdle. A round brilliant diamond has sixteen upper girdle facets.

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V:

Valuation: (Or Appraisal) is a written statement giving an independent and expert opinion as to the worth or current value of your jewellery as well as an accurate description of it.  Insurance companies require a written appraisal/valuation to ensure adequate compensation or jewellery replacement in the event of a loss occurring.

W:

Wedding Ring: Or wedding band, consists of a metal ring which is exchanged during the wedding ceremony to symbolize marriage: a spouse wears it to indicate a marital commitment to fidelity. In some countries it is worn on the left ring finger. In others, it is worn on the right ring finger. Some prefer to match the wedding ring to the engagement ring however this is really a personal preference.

White Gold: White gold is an alloy of gold and at least one white metal, usually nickel or palladium. Since this alloy is never truly white, it is almost always plated with rhodium, a shiny, white metal which is also extremely hard. Wear and tear on jewellery will cause the rhodium plating to wear off, revealing the original metal colour. This is easily remedied by having your jewellery replated to bring back the whiteness and make it look new again.

Wing: One of the two sides near the point of a marquise, pear, or heart shaped diamond.

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Y:

Yellow Gold: The natural colour of gold. It is used to create jewellery as it is the most malleable and ductile pure metal known. It is dense, soft, shiny, and does not tarnish, rust, or corrode. For jewellery it is measured in karats. See karat.