When you look at diamonds in jewelry stores, they may all seem colorless. But if you look closely, you'll notice that they normally have slight tints of yellow, gray or brown. The strength of these tints partially determines the price of the diamond. Normally the less color a diamond has the more it costs. However, prices start rising when the color reaches a point just stronger than light yellow (a grade designated as fancy yellow). As the intensity of fancy-yellow diamonds increases so does th...