Since the advent of diamond mining, diamonds have been prized for their clarity, transparency and purity. In fact, the finest diamonds were historically referred to as “gems of the first water”—such that the purest diamonds mimicked the color of the clearest drop of water. This age-old comparison was even noted as early as 1607, in Shakespeare’s Pericles:
Heavenly jewels which Pericles hath lost,
Begin to part their fringes of bright gold.
The diamonds of a most praisèd water
Doth appear, to make the world twice rich.
Shakespeare, Pericles (Act III, Scene 2)
Nowadays, diamonds are graded on internationally recognized scales for both clarity and color. The majority of diamonds possess varying levels of nitrogen in their chemical composition, which give them a slight yellow tinge. Colorless diamonds that possess very low levels of nitrogen are exceptionally rare and command extremely high prices at market—with prices per carat consistently increasing over time.