DIAMOND COLOR TREATMENTS

Diamonds that are light brown, light yellow, or colorless may have their colors altered to blue or blue-green by irradiation treatment. If the green material is then heat-treated, it may change to brown, orange, or yellow. Some of the diamonds that have been altered to yellow also have a chance of turning pink. Recently, irradiated red diamonds have also been noted. The photographs show some of the characteristic colors of diamonds that are color-treated. Their uniform coloration gives them an artificial look, and a person experienced in dealing with gemstones can usually tell the difference between natural and artificially induced colors. It is also possible to positively identify natural and treated colors by observing a diamond's absorption spectrum.

Color-treated diamonds are not commonly used in traditional jewelry, but when they are, the buyer must be informed that the diamond has been treated with radiation. Color treating diamonds makes it possible to take relatively low-quality material and alter its color to blue or yellow. If the price of a one-carat, naturally blue diamond were $100,000, then an irradiation-treated blue diamond - even of comparable color - would have a totally different value, costing about $2,000 to $3,000.