A gem is often chosen for its color, and yet the diamond is alone in having its own internationally recognized color scale, defined by professional bodies. This scale distinguishes white or colorless diamonds from fancy colored diamonds. Actually the white diamond offers a rich variety of nuances. Color is even one of the four qualities by which this precious stone is judged (one of the famous four “C”s, along with clarity, cut and carat). The diamond’s color is determined by comparing it with a master set of stones which have already been color-graded by experts. They are presented in a case. The stone to be color-graded is placed on a sheet of white bristol board next to one or more diamonds from the master set.