Color in Diamond Grading

The second C used in rating diamonds is color. Diamonds come in literally every color in the rainbow and while a few specialty colored diamonds are extremely valuable because of their deep hues and unique color characteristics, these are the exceptions rather than the rule. In general, the closer a stone is to possessing no color, that is, to being colorless, the more the stone is worth.

In order to establish the transparency or lack of color in a diamond, the loose stone is placed on a pure white background under a white light. There are special lights sold with adjusted color temperatures for this viewing or some people prefer to use the soft north sunlight when trying to view the color of a diamond.

In color rating as in clarity rating, the dazzling brilliance and fire of a diamond are the viewer's natural enemy. They will confuse the eye and care must be exercised to not become jaded or tricked, but rather to view each characteristic individually and in comparison to other stones or photographs of stones.

The most accepted color grading system is that again of the GIA.  Their system is judged by using a series of master stones sold by the GIA or their representatives that establish hues and tints and can be laid side by side with the stone in question in order to view how white the stone really is.

If at all possible, it is certainly worth one's time to visit a large gem dealer with the intent or apparent intent of purchasing a good-sized stone and ask to see a master set and become used to judging the color on several stones until you have a feel for the concept of whiteness, transparency and hues.

Technology has now produced a practical and inexpensive (comparatively) method of possessing your own diamond master stones. These stones are available in all colors D through Z on the GIA scale and are excellent to have on hand to compare with any other stone you may be considering purchasing in order to rate the new stone. These stones are color correct because they're created to be exactly the color they're supposed to be.

How can this be cheap? The stones are not diamonds. They're CZ's, cubic zirconium. These CZ stones look like diamonds, act like diamonds, smell like diamonds and can be matched to a real diamond in order to compare colors with an extreme degree of accuracy.

There's also a device known as a color meter which electronically measures the color or lack of color in a stone. This meter is quite accurate although fairly hard to come by unless one is a member of the Gemological Institute of America.

Source: Video Vindicator, 1992, BBS.