How Does an Oyster Make a Pearl?
The inside shells of oysters and other shell-forming mollusks are covered with a shiny, lustrous substance called nacre, or mother-of-pearl. Only tropical sea pearl oysters have the beautifully colored nacre necessary to make valuable pearls. Other edible clams and oysters also make pearls. But we would not recognize them as pea
A grain of sand accidently falls inside the oyster and the irritation from the sand causes the oyster to coat it with layers of aragonite, conchiolin, and nacre, which makes them shiny. The larger the grain of sand, the larger the pearl. Most pearls today are made by humans by purposely injecting a bead into the oyster.
A pearl is a natural gem created by a living organism. When a foreign object is introduced into a mussel or oyster the animal coats the irritant with a substance called nacre, the same material with which it builds it’s shell. Over time, the layers of nacre build up to form the pearl. The longer the irritant remains in the mollusc, the more layers of nacre and (usually), the better the pearl.