Pink diamonds are different from other fancy colors in that they do not get their color from any trace element such as yellow and blue diamonds do. Instead, after their formation, these stones are subjected to very high temperature and non isotropic stress which deforms the crystal lattice and displaces some of the carbon atoms from their regular positions. It is accepted today that these structural defects are the cause of a diamonds pink hue.
In Pink Diamonds these defects are very obvious and can be seen as "graining lines" with the help of a microscope and in some cases even apparent to the naked eye.
Like other colors GIA grades pink in terms of tone hue and saturation. As tone and saturation increase rarity goes up as well as value. Starting from low tone and saturation and increasing GIA grades pink diamonds as light, fancy light, fancy, fancy intense/ fancy deep, and fancy vivid. Pink diamonds are unique in that when a stone falls into the rare category of extremely high tone and saturation GIA uses the term "fancy RED" to classify it.
Pink diamonds have only been found in a few mines across the world. The rich Golconda region in India and the Minas Gerais region of Brazil produced notable diamonds in the 17th and 18th centuries. Today, the Argyle mine in Western Australia is the source of the vast majority of the world’s supply. It is famous for generating the hugely coveted full- bodied hot pink diamonds.