Pearl Color Treatments
There are three main pearl treatments that low quality pearls are subjected to 1) dyeing, 2) irradiation, 3) luster enhancements. Dyeing Pearls
Dyeing includes the use of silver nitrate on the pearl, in order to darken the pearl’s nacre. Irradiation treatments use gamma rays to darken the pearls. Black pearl necklaces that have been color treated include Akoya pearls, which have their nucleus darkened by the gamma rays, while freshwater pearls have their nacre darkened. Luster Treatments
Luster treatments are typically a clear coating placed on the surface of the pearl in order to artificially increase the luster of the otherwise dull looking pearl. Pearl Distributors do not sell any pearls with luster treatments. Black pearl coloring
The use of silver nitrate has been used for many years to enhance pearls. This chemical penetrates the pearl, has a chemical reaction to either sunlight or hydrogen sulfide gas, and in turn can create a rich black colored pearl. Other colors can be created as well using this method, along with both organic and inorganic dyes. With the freshwater market came increased opportunities for pearl processors to experiment with these methods. The reduced cost of freshwater pearls created the perfect scenario for trying out new treatments. Pinking Pearls
As for Akoya Pearls, they can be subjected to this process in order to create a much sought after "Rose" overtone which is very popular in pearl jewelry. Almost all pearls are being treated one way or another today. Detecting color change treatments can be tricky. But here a few methods one can use: How to Identify Color Treated Pearls
1) one can examine the matching of the strand of pearls. A strand of natural colored pearls will have slight color variations between each pearl. A perfectly consistent strand of pearls can be evidence of color treatments. Perfect pearls are not natural.
2) One can peer down the drill hole of a pearl and look for contradictions of color. If one can see a darkened nucleus when peering through the hole, this could be evidence of iridescent treatments.
3) Sharp colors are another hint of an enhancement. It is common to dye poor quality Peach colored pearls “Pink”. Keep in mind that natural pearl colours are pastel and have a soft look to them. Bold sharp colors are normally enhanced.