Why is there a need for cultured pearls? Natural pearls are very rare and extremely valuable, only one oyster in forty may contain a pearl. A natural pearl starts as a foreign particle (a pebble, a fragment of a shell, or a grain of sand) in an oyster or mollusk. The particle irritates the oyster and it secretes a substance called nacre. The nacre protects the oyster from the particle. Over the years, layer upon layer of nacre adhere to the particle, which results in a pearl. Due to the rarity of natural pearls, only the wealthy and royal were able to afford them prior to the invention of “cultured pearls”.
In 1893, Kokichi Mikimoto, invented a viable technique for producing hemispherical “cultured pearls” in Japan. Mikimoto created this technique of seeding an oyster with an irritant, which is the only difference between a cultured pearl and natural pearl. Mikimoto seeded the oysters with a small bead of mother of pearl. He found that the pig toe clam shell from the Mississippi River has similar genetic properties to the Akoya Oyster he used, therefore it lowered the chance of being rejected by the oyster.
It took Mikimoto another 12 years to culture completely spherical pearls by also inserting a small piece of mantle lobe tissue from another oyster during the seeding process which begins to deposit a nacreous coating over the bead. These pearls rivaled the appearance of high quality natural pearls.
Today, the cultured pearl industry includes Akoya cultured pearls, South Sea cultured pearls and Tahitian cultured pearls produced by salt water pearl oysters, as well as freshwater cultured pearls produced by freshwater mussels.