Diamond cut or shaped into a rectangle with the corners cut off, and rows or steps of elongated facets running parallel to the girdle on both the crown and the pavilion.
Emerald Cut
Durability
Overall resistance to wear and damage, considering both hardness and toughness. Diamonds are the hardest gemstone on earth, but are not the toughest – they have directional hardness.
Eight Cut
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.
Dispersion
Directional Hardness
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.
Diamond Dust
Minute particles of diamond, usually used as a high-quality abrasive for diamond polishing or industrial grinding, sawing, and filing.
Diamond Gauge
Tool used to manually measure the dimensions of a diamond.
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.
Depth Percentage
Diamond
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.