Generally, diamonds are considered to be perfect when they have a pure white colour.
An exception to this rule, however, are fancy diamonds: All diamonds that are out of the usual colour scale from D (perfect white) to Z (yellow).
Diamonds can appear in all colours. The rule for fancy diamonds is that the more intense their colour, the more desirable they are.
This Fancy Diamond in the shape of a heart was made into a stud earring.