The absence of color is characteristically a marker of quality in a diamond, along with the other 3C's of diamond grading: Clarity, carat, and cut. The less color a diamond possesses, the more true color it reflects, resulting in that brilliant sparkle that has been valued since time immemorial.
Unlike their colorless counterparts, which exist in fairly large quantities in nature, fancy color diamonds constitute an ever shrinking percentage of the rough diamonds mined and manufactured each year.
Although if you hear the word “diamond” you typically think of a brilliant, colorless stone, diamonds in fact come in many different colors. The ideal colorless diamond, graded D, is completely clear because it is made of 100% pure carbon, but this is pretty much impossible to find in nature.