Pearls

A pearl is a hard object produced within the soft tissue (mantle) of a living shelled mollusc. A pearl is made up of concentric layers of calcium carbonate deposited in minute crystalline form. The ideal pearl is perfectly round and smooth, but many other shapes of pearls (baroque) occur. Cultured or farmed pearls from pearl oysters and freshwater mussels make up the majority of what is sold today. Gem quality pearls are almost always nacreous and iridescent, as is the interior of the shell that produces them. Pearl is 2.5-4.5 on the Mohs scale and is considered the birthstone of June.