Even though they are transparent, most diamonds contain some hint of color. This is caused by the presence of nitrogen in the earth where they formed. Diamond color grading is done on a scale of D to Z.
D is ‘icy-white.’ These diamonds are the most colorless and most rare, so they are considered most valuable. There are 23 descending grades, so the increasing hints of color are very slight. The average person cannot distinguish between several color grades. D, E and F diamonds are all considered colorless to normal vision. G, H, I and J are called near-colorless but still considered to be in the white range. K through Z are faint yellow to yellowish or brownish. A diamond with more color than a Z is a ‘fancy colored diamond’ and could be a different color like pink or blue.
Color
Diamonds are graded in the face-down position and viewed for color from the side. This is because great light return in a diamond can ‘mask’ color, especially in round brilliants. Extremely well-cut diamonds may appear more colorless in the face-up position than the grade they received at the lab due to superior light return. For instance, a diamond that was graded H in the side position can ‘face-up’ like a G or an F, but only if it was cut extremely well.
Color and Sensitivity
Some people are more color-sensitive than others. One person may see color in a diamond that appears to have no color to someone else. Even if you have great sensitivity to color you may have different preferences than others. The icy whiteness of a D may appeal to one person, while the warmer look of a J appeals to another. A third person may not see any difference between the two.
Color and Settings
Remember that diamonds absorb the color of their surroundings, so it’s best to judge them against a white background. Once mounted a diamond will show less color than it did loose. Remember that the choice of setting may influence your diamond’s color. If you choose a gold setting and have a colorless diamond that diamond may absorb and reflect back some of the setting color.
Color Enhancement
High Pressure High Temperature treatment (HPHT) is a process where a diamond is irradiated to improve its color.
