One of the most beautiful gemstone is not a stone at all. The pearl is one of the most impressive looking gemstones and because the material that a pearl creates is the same material that can be found in the earth’s crust (calcite) it is called an organic gemstone.
Pearls come from the sea; usually three types of animals (bivalve mollusks) are responsible for creating the majority of Pearls. They are oysters, clams, mussels and abalone.
A pearl is a natural defense reaction to an unwanted irritant in the mollusks body. For instance, if a small particle such as sand, a piece of shell, or a parasite finds its way into an oyster’s body, the oyster will defend and protect itself by creating a protein that will render the particle harmless. This protein is calcium carbonate and it is the same crystalline form as other precious minerals such as aragonite or calcite.
Pearls usually take a few years to form and the way it forms is through the mollusk continually wrapping the particle in this calcite protein. Pearls are extremely beautiful, come in many sizes and rare when found in nature. They are usually white; however they can have tinges of blue and green or come in black or silver. Pearls are very smooth and sometimes iridescent due to the small structure that the calcite is made from. Light waves make the pearl seem many colors at once or give it an aura type quality.
Pearls have been known to man for thousands of years, however it is only recently that pearls have been farmed and cultivated. Cultured pearls started in Japan at the end of the 19th century and by manually placing a small particle in mollusks, the pearl farmer is able to spur pearl production. Today, the vast majority of pearls for sale are cultured. However, cultured pearls are practically indistinguishable from their real counterparts and just as beautiful.