For white diamonds, color grades indicate the lack of color. Color is widely considered the second most important characteristic after cut, as the color grading scale determines the whiteness of your diamond. How high a diamond will be graded on the scale will be decided by the least amount of color in the stone. Completely colorless diamonds are at the top of the color grading scale as D, E or F. These are the rarest and most expensive color grades.
When moving down the color scale to G, H and I, diamonds will begin to manifest extremely slight nuances of yellow, which typically cannot be detected by the untrained eye. Further down the scale, diamonds begin to reveal more color.