Cultured Freshwater Pearls

Pearls are one of a few natural or organic gemstones (others include coral, amber, jet and mother-of-pearl). Produced by the pearl oyster and the freshwater pearl mussel, natural pearls are a small irritant within the oyster or mussel which has been coated with nacre to reduce that irritation. Concentric layers of nacre (composed mostly of the mineral aragonite) create the subtle iridescence and illusion of visual depth in pearls (called "pearlescence").

Natural or "wild" pearls are rare and valuable so most pearls today are cultured. Saltwater and freshwater mollusks are collected and a small shell bead placed inside. Saltwater oysters can usually only generate a single cultured pearl at a time, while the much larger freshwater mussels can produce up to 20--which is why freshwater pearls are much less expensive. The mollusks are then returned to the water where they make the pearl. Layers of calcium carbonate are secreted, coating the piece of shell, to form a spherical, oblong or irregular-shaped (or "baroque") pearl. It takes roughly 3 to 7 years for mollusks to produce a single pearl. The color of the pearl varies depending on the type of mollusk. (The oysters and mussels that make the pearls are not related to the edible varieties of oysters and mussels.)

Most natural and cultured freshwater pearls are found in the waters of Japan, China and the South Seas; however, many are harvested along the coasts of Australia and the rivers of Austria, France, Scotland and Ireland. Cultured freshwater pearls are also grown along the Mississippi River in the United States.

Caring for Freshwater Pearls

Pearls are soft and should be treated delicately. Never use ultrasonic cleaners or steamers. Wipe gently with a soft cloth after each wearing or, for more thorough cleanings, use mild soap and water. If knotted, make sure cord is completely dry before wearing.
Human skin oils are one of the best things for pearls. Pearl owners should wear theirs often enough to keep them looking lustrous. Take care to not use perfumes, colognes or lotions where pearls will be touching the skin as the gems will absorb what they come into contact with. Avoid lotions and skin care products which contain citrus oils, as even mild acids can dull the surface of pearls. Always remove pearls before engaging in exercise, as perspiration can also negatively affect the surface.

Source: Firemountain Gems