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Diamond Glossary

 A–Z of Diamond terms

Bearded Girdle (BG)
Often formed as a result of the manufacture and cutting of the polished Diamond. Microscopic feathers extend from the surface of the girdle into the Diamond.

Bruise (Br)
A small mark on the Diamond, resulting from impact, which extends into the Diamond, below the surface of the stone. These small marks often appear where two facets meet where the Diamond is more exposed to damage.

Cavity (Cv)
Where part of a feather breaks away from the Diamond, a small crack-like opening, the cavity appears.

Chip (Ch)
Impact or pressure can cause Diamonds to chip. Chips are damage and can vary in size and shape, but typically appear as breaks in the stones surface, often seen at the point of the Diamond, the edge of a facet or culet of the stone.

Cloud (Cld)
Clouds are formed by much smaller inclusions grouped in one area. Alone they are too small to be readily visible, but together they are more noticeable and slightly foggier and distinct.

Feather (Ftr)
A white inclusion, feather-like in appearance usually formed by a fracture within the Diamond.

Grain Center (GrCnt)
Caused by distortion of the Diamond crystal, appearing either as light or darker markings within the Diamond usually thread-like or of pin-point appearance.

Crystal (Xtl)
Inclusions caused by crystallized mineral inclusions.

The direct result of dispersion caused by white light separating into spectral colours as light passes through the body of a Diamond.

Indented Natural (IndN)
A natural indent within the rough-Diamond appearing in the polished Diamond's surface.

Internal Graining (IntGr)
Lines, Curves and inclusions appearing at angles. These can be white, coloured or semi-transparent, caused by irregularities during diamond crystal formation.

Knot (K)
This is a transparent included diamond crystal present within the diamond itself, extending to the surface following the process of cutting and polishing.

Laser Drill Hole (LDH)
A fine, straight hair like line which extends from the surface of the Diamond. Laser drill holes are the result of a beam of laser drilling into the Diamond, typically part of the process for clarity treatment.

Abbreviation. Light Brown, a brown colour associated with a certain type of Diamond colour, typically between M to N colour on the GIA scale.

Needle (Ndl)
A thin, needle-like inclusion, which can vary in length.

Pinpoint (Pp)
A small dot-like inclusion, within the Diamond.

Refractive Index (RI)
Abbreviation. A measure of the change of speed and angle of light as it passes from one material to another.

The change in speed and possible change in direction of light as it travels from one transparent material to another

Smoked Diamond
Excessively high temperatures will cause the surface of the Diamond to form a layer of oxidation. This layer is commonly referred to as smoking and can only be removed by re-polishing the surface of the Diamond.

Abbreviation. Top Light Brown, a light brown colour attributed to tinted Diamonds usually between L to M colour.

Abbreviation. Top Top Light Brown, a light brown colour attributed to tinted Diamonds usually between J to K colour.

Twinning Wisp (W)
A series of pinpoints, clouds or crystals that forms in a Diamond's growth plane; associated with crystal distortion and twinning planes.