GEM CUTS

Today, diamonds may still be altered in similar ways, such as a coating on the pavilion to give them a better color. Jade- can be stained d or dyed, and serpentine-which resembles jade-can be -d, too, to look like jade. Opals may be coated black on the to give the appearance of valuable black opals, while opal doublets may be glued together with black cement for the same.

Turquoise can be soaked in wax or impregnated with wax to e the color. Other stones can also be altered in these and always to improve the color. One indication of an altered stone rice that seems too cheap for a genuine gem of that color.

The color of stones can be altered in other ways that may take an expert to detect. Some stones can be heated to improve the Unattractive brown-colored zircons can be changed to color blue stones by heating, making them more valuable.

Irradiation by gamma rays is another way to change color. Off-color diamonds, when irradiated, become desirable brown, yellow green colors that can command a higher price as "fancies." United States, irradiated stones must be marked "irradiated" according to Federal Trade Commission regulations, to distinguish them from higher-priced natural stones. Irradiated stones are more in demand Europe, where colored stones have always been more in wd than in the United States, where colored stones are susceptible whims of fashion.

The results of both heating and irradiation, nevertheless, can be very desirable-as long as you know what you are getting. This is especially true of heated stones, which can sometimes fade or I color.

Gem substitutes, therefore, can be a problem and will be treated specifically in the next chapter under the particular gems. Being where you buy and from whom you buy is the best way to avoid being cheated. Few reliable jewelers would knowingly sell a substitute gem as a genuine one; if they did so unknowingly and the substitute was detected, they would make good on it for the sake of their reputation.