| The type of bleach used can determine whether or not damage occurs to the pearls.
Akoya pearls and freshwater pearls are almost universally bleached. Akoya pearls are very, very commonly pinked as well. The bleach can damage the pearls if it is too concentrated. The reason some factories use strong bleach is due to a quicker ROI. This can damage the nacre of the pearls, and this nacre can/will turn brittle, and may darken.
Pinking, on the other hand, does not seem to damage the pearls. It can actually increase the value of the pearls substantially, as creamy color pearls are much more difficult to market than rose color pearls. Pinking is typically easy to spot by looking for concentrations of color on the surface of the pearls, and in the drill hole between the nacre and the nucleus.
The easiest was to ensure you are not buying pearls that have been improperly bleached is to buy high quality pearls from a reputable dealer. These pearls will have a good thick nacre. Thin nacre pearls (cultured for only 6-9 months) are typical of the pearls you will find improperly bleached.  |