How are pearls formed?
Pearls are formed within the bodies of mollusks (water animals with soft bodies and a covering of hard shell, such as oysters found in saltwater bodies such as seas and oceans and mussels found in fresh water bodies such as lakes and rivers). Sometimes a foreign material, usually a sharp object such as a sand grain, enters the body of the oyster or clam. This irritates the mollusk, but it is unable to expel the particle. In order to relieve itself from the irritation it secretes a liquid called nacre and coats the particle with it. Layer upon layer of nacre solidifies around the particles resulting in the formation of a pearl. It takes anywhere between three to six years for a pearl to form. Nacre is the same secretion that the mollusk uses for building its shell. Chemically, it is a combination of calcium carbonate and an organic compound called conchiolin. Nacre in popular parlance is known as mother-of-pearl. The layers in a pearl are translucent. Therefore, both reflection and refr
