The Diamond Certification Laboratory of Australia (DCLA)

Diamond cut or shaped into a rectangle with sharp corners, and rows or steps of elongated facets running parallel to the girdle on both the crown and the pavilion.

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.

Kite-shaped facets on the crown of brilliant cut diamonds. Also known as “top-main” facets.

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.

An informal and often misused trade expression that refers to a completely colourless diamond. The diamonds were usually lower cape series diamonds with strong blue fluorescence.

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.

An unpolished diamond girdle, with a rough or frost-like appearance. The girdle may be either bruted, faceted, or polished.

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.