Before the mid-18th century, the most exceptional diamonds by their size and purity came from India. It is from the mid-18th century has been discovered in Brazil and South Africa extraordinary stones.
Diamonds can be outstanding either by their weight, purity or color. When they combine the the three qualities, we can say they are extremely rare.
Because colored diamonds are much rarer than white diamonds (colorless), some colored diamonds (yellow, pink or blue) are considered outstanding even though they have a much lower than their colorless concurents weight.
Thus, among these, only about 350 were differentiated by their exceptional characteristics and received a specific name that makes them unforgettable ever.
Their value is, for the largest of them, and they have the invaluable privilege enthroned on royal jewels.
The more modest category belongs personalities sufficiently wealthy to acquire these gems.