A cultured pearl is a pearl created by a pearl farmer under controlled conditions.
A cultured pearl develops in the same way as a natural pearl in the wild. Pearls are created from the core of certain shellfish, mainly oysters and mussels.
The core of a natural pearl is simply a fragment of shell or a grain of sand. A pearl forms when an irritant enters the shell. The mollusc then secretes layer upon layer of calcium carbonate, known as nacre, around the foreign body. It is this innate defence mechanism that creates the bead of pearl.
The only difference between a cultured and a natural pearl is whether the irritant is implanted or not. The cultured pearl's irritant is created from pig-toe shell (clam shell) in the shape of a round bead. The pig-toe shell has similar genetic properties to the Akoya oyster and therefore lowers the chances of being rejected by the oyster.
Whether natural or cultured, pearls are created by forces of nature.
Cultured pearl was first developed by the British biologist William Saville-Kent who passed the information along to Tatsuhei Mise and Tokichi Nishikawa from Japan.In 1889, he became Commissioner of Fisheries for Queensland, and in 1892, Commissioner of Fisheries for Western Australia, a position he held until 1895. During this time he experimented with culturing pearls; his experiments were successful, and modern-day spherical cultured pearls are primarily the result of discoveries he made. These discoveries were later patented by Dr. Tokichi Nishikawa of Japan, who had heard of Saville-Kent's techniques. Later, Saville-Kent went on to chair the Royal Society of Queensland from 1889–1890.