Do pearls really form from a grain of sand?
Contrary to popular belief, pearls hardly ever result from the intrusion of a grain of sand (inorganic material) into an oyster s shell. Instead a pearl forms when an organic irritant becomes trapped in the mollusk. An organic irritant can be a result of injury or an intruding parasite. The animal senses the foreign object and coats it with two materials a mineral and a protein that results in mother-of-pearl, the substance called nacre (NAY ker). The work belongs to the animal.
