The rarest and most valuable diamonds in the world are those that come closest to having no color at all other than the very rare diamonds called “fancies” such as blue, red, or green, pink or intense yellow. However, color is only one of the four criteria by which a diamond will be judged. Equally important are cut, clarity and carat weight. So the closer a diamond is to flawless and without color the rarer and more valuable it will be.
Diamonds that have no color at all are extremely rare and therefore more valuable than those that are tinted white.
There are a number of internationally recognized grading scales, all of which will enable you to judge the quality and value of your diamond. These scales are by an large compatible but may well use different nomenclature. G is a description most commonly used by the laboratories and you should consult your jeweler on how other scales express the identical grade.