Many articles on diamonds, as well as published articles in many fields, have provided useful information dealing with diamond.A diamond is probably the most universally known of all minerals because of its mearly 3000 years in history and tradition and extending to modern times times it is still a symbol of constancy and love. Diamonds account for over 90 % in money value of the world's gem trade.
Identification of a diamond, usually very simple to the experienced person, is not always so simple. Diamond being a very hard stone, when well polished has an extremely high luster, unequaled by other stones. When well cut, practically all light striking above the girdle part of the diamond, will be returned to the eye by the back facets.
With most gems of lower refractive index, a finger or other object held behind the gem will be visible to some extent. This is not true when looking through a well cut diamond. Nothing is seen through the stone. This total reflection is one of the factors causing diamond to be considered a brilliant gem. Another factor is its complete transparency. Very little light is absorbed by its passage from the top facets, its reflection from the back facets, and return to the eye.
All of the information above is relating to a diamond of good quality. But if the stone examined is of poor quality with some internal haze, poorly cut, cut too deep or too shallow, poorly polished, or cut as a thin baguette. Or it might be of some odd color causing doubt as to its identity. Then, some testing might be necessary.
The simplest test, one quite often used, is the much frowned on hardness test. Diamond is the hardest of all minerals. The hardness test may be sufficient enough if it is only to show if it a diamond or not. There are relatively few stones that could be mistaken for diamond. Zircon, synthetic colorless spinet, synthetic colorless sapphire, colorless topaz, synthetic rutile, strontium titanate, and glass.
