Most diamonds appear colorless but actually have slight tones of yellow or brown. The closer the stone comes to colorless, the more valuable it is. Diamonds are graded on a color scale ranging from D (colorless) to Z (heavily tinted.) Only a highly skilled professional will detect any color in E or F stones, and the color in diamonds rated up to J will be virtually invisible when set in a ring or other jewelry.

Color is only one of the four C's so even when a stone has a visible tint, such as K or above, it can still be very lovely if it has good clarity and cut. How the diamond is set can make a difference, too; you might not want to put a truly colorless diamond in a yellow gold setting since the yellow color will reflect in the stone. On the other hand, a slightly yellow stone will appear whiter in a yellow gold setting.