Like most other gems on the market today, pearls can be treated to improve their color and other attributed to make them appear more valuable. When buying pearls from a jeweler, always ask for full disclosure on any treatments that have been done and make sure they are listed on the bill of sale.

Some pearl treatments are more acceptable than others. For example, virtually all pearls are tumbled to improve surface quality and shine. Most pearls are also bleached in some fashion to improve their make on a necklace - this provides a more consistent look to the jewelry piece. Some treatments are not as accepted and can in fact damage the pearl.

Then there are the obvious scams, false claims, and misrepresentations. For more information, see pearl scams and imitation pearls.