Bleaching Organic substances like ivory and pearl come from nature with various discolorations. In a manner similar to removing clothing stains, gem dealers bleach these materials to whiten and improve their appearance. Bleaching is also used to lighten the body color of gems like the tiger's eye. Such enhancement intensifies its shimmering bands of color. Golden coral is also the product of bleaching.
Some diamonds contain natural internal black spots.
Jewelers make these inclusions less noticeable by using a laser to open a minute channel in the gem. A whitening solution is then injected into the channel to lighten the inclusions. To date, this high-tech enhancement is used solely for diamonds.