The purpose of the current optimization of the pearl is to improve grades, increase their economic value. For mariculture beads, pearl colors are generally no need to change color, only black pearl production due to less expensive, so before the light changed to a dark-colored pearls, they are:

     1. Staining (plus color) Act. And ammonia solution will be, and then a good soak in the sun or pearl on the reduction of hydrogen sulfide gas, so that the color of black pearls. Brown product of such a black, green, black and black colors with natural pearl is very similar to the same color and the color of the treated light and heat stability.

     2. Discoloration-ray irradiation method. Pearl color radiation treatment to deal with the largest number of black, and similar to the natural black pearl. The method is to drill on the source of pearls under the radiation from the black, the color of the light and heat stable, this method to deal with the Black Pearl because it is extremely rare dose had no effect on the human body.