With so many types of pearls to choose from, it’s not surprising that there is some confusion.
Natural pearls are rarely found in any quantity these days, so basically there are 3 types to choose from: Tahitian South Sea Pearls, Cultured Akoya Pearls and Freshwater Cultured Pearls. There are also Simulated Pearls which are manmade, more about those later.
Firstly a little bit about the development and process. When an oyster or mussel has an irritant inside it’s shell, it coats it with a secretion called nacre (also known as mother-of-pearl) to prevent damage to the inner shell. It continues to build up layers of the nacre until it forms a pearl.
Cultured basically means man-assisted. The oyster or mussel is gently opened and a nucleus of either, a mother-of-pearl bead or piece of mussel mantle, is placed inside. The size of the pearl required depends on the size of the inserted bead or beads. South Sea Tahitian and Akoya pearls are all grown in oysters at sea, by the Japanese. Whereas, freshwater pearls are grown in mussels inland, by the Chinese.
Japanese Cultured Pearls. Looking after the oysters at sea is an intensive process. They are grown in cages attached to rafts. Whenever sea conditions become poor, the rafts have to be moved to shelter. Otherwise the pearls will become ridged and pitted. They also have to regularly cleaned and cared for. It takes a minimum of 1 year, usually more like 3 years, in order to create pearls of a bright lustre with a thick coating.
Freshwater pearls are easier to care for as they are protected inland. Shape is a little more difficult to maintain though, as there isn’t space for a bead nucleus, so a piece of mussel mantle is used. This is a much easier process, not requiring such a technical staffing level. However mussels are smaller than oysters which limits the size of pearls which can be cultured. It’s unusual to find them much larger than 10mm and the price increases considerably above that size.
The Chinese freshwater pearl industry has become so successful that the Japanese cultured pearl industry is threatened and the price of these are much reduced in comparison.
Tahitian South Sea pearls are highly prized. The oysters are very large, allowing much larger pearls to be cultured but they take between 3-5 years to form.
Colours of pearls apart from white can be a natural pink. In the case of South Sea pearls, grey and black are from the black lipped oyster. Other colours are usually created by dying or treating.
Simulated pearls are created by dipping or spraying a coating made from fish scales onto a glass bead. Imitation pearls are usually plastic with a thin pearlescent material coating.
Care. Pearls, as they are a natural product, are damaged by perfume, hairspray and any skin acidity. They should be removed for showering, bathing and sleeping. They will wear with time, making the pearl surface thinner. If they are regularly rethreaded and treated with care, they will last a lifetime.