Bleaching

Some gemstones can be bleached to remove an unwanted colour. In some cases this is done with acids, in other cases with hydrogen peroxide or similar oxidizing agents. Only certain gemstones can be bleached.

Jadeite is often found with iron staining, due to natural iron oxides (such as limonite) found in the rock. Acid treatment of Jadeite can remove the iron oxides, but leaves the jadeite degraded so that it must be polymer impregnated to stabilize it.

Pearls are also bleached, with hydrogen peroxide, to enhance their appearance. It is also part of the process for creating the "chocolate" coloured pearls, treated from black pearls.

Anglesite, a lead sulphate mineral, is freqently bleached to turn it into a strong yellow colour - however as with most bleachings, the effect is only confined to a thin superficial surface layer which is easily damaged and removed, so has to be done after material is cut, and gems treated this way are not resilient.

Search all Bleaching cut gemstones
Treatment List