This color grading system and chart was developed by the Tanzanite Foundation, www.tanzanitefoundation.org The color quality is based on the degree of saturation with greater value placed on gems with greater saturation. The first color listed is the modifier and the second color listed is the primary color. Not shown are those gems that are rarely seen in the market of extra-ordinary color which are given the quality rating of exceptional plus. E+. The common and less accurate grading of AAA would include those gems rated intense, vivid and exceptional. Blue violet gems show more violet color and in daylight will still show a noticeable component of violet color while violet blue gems show more blue in incandescent light and will show little to no violet in daylight.
Although the deeper colors have greater value this does not mean that some of the lighter colors like those of moderate color are not desirable. When you add a fine cut to a moderate color it can be a gem of great beauty.