Tuamotu

Natural pearls:
Definition:" Hard, shiny, precious concretion formed from circular layers of mother-of-pearl secreted by the mantle epithelium of certain mollusks in order to surround and isolate a foreign body or parasite. "
Natural pearls thus come about accidentally due to the presence of a foreign body in the living oyster (particle of sand, piece of coral etc). Using a natural process, the oyster will create a layer of mother-of-pearl to surround this object. This mother-of-pearl or nacre, is essentially composed of calcium carbonate in the form of the mineral aragonite. Due to the over-harvesting of ‘wild’ oysters for farming, natural pearls are extremely hard to find nowadays.

Naturally colored cultured pearls:
It was through observing and understanding this natural process that people first had the idea of deliberately placing a foreign body (called a nucleus), such as a piece of shell from another species of mollusk, into the oyster’s intestinal sac. It is necessary to wait for between 18 months to two years to begin the grafting process on the oyster (which will be between 7 and 10 cm in diameter) then another 18 months, during which the oyster must be watched over and protected from predators (fish, turtles, rays, people). The exact time period involved depends on the atoll lagoon, each lagoon being different from another in terms of plankton and the tides. It is still necessary to look after the oysters through regular cleaning designed to eliminate parasites that may attach themselves to the oysters, such as anemones, "pipis" (small mussels) and invasive algae. This cleaning is carried out using high pressure water sprays or by hand with a knife. The financial costs of this upkeep are very high and represent a significant proportion of the long-term investment involved in pearl farming (qualified divers, cleaning equipment, boats etc). The cleaning does, however, improve pearl quality by the time harvest comes. An ongoing program of grafting during this gestation period ensures a steady supply of pearls and helps offset the farm’s running costs. The production of cultured pearls is largely concentrated in the islands of the Tuamotu Archipelago, one of 5 archipelagos that form French Polynesia, of which TAHITI in the Society Islands is the capital. If you placed French Polynesia onto a map of the world, its area would cover all Western Europe and part of Central Europe.

The Nucleus – A shell bead:
The shell nucleus is a round bead, with a surface that is smooth, polished and flawless (with no pores, cracks, or scratches occurring either naturally or during the manufacturing process). The choice of shell and the sorting of the finished nuclei are the two most important initial steps since they are crucial to the ultimate success of the pearl harvest. It was a Japanese national, Kokichi Mikimoto, who tested and confirmed the very good results that could be achieved using "Ligumia Recta " (common name – Black Sandshell), found in the Mississippi River. The good water quality of the river and the size of these shellfish meant that they made excellent material for nuclei, compared with other materials that had already been tested - plastic, ceramic and glass to name a few. Grafts were more successful, rejection rates lower, and jewelers found the resultant pearls easier to drill and work with generally. However, in 1998, the mostly Asian-based makers of these nuclei brought poorer quality nuclei (made from clams and other shellfish species) onto the Polynesian market. This has had a negative impact on the quality of Polynesian pearls up to the present day. Consequences: Pearls are more difficult to drill, the pearl may suffer surface cracking, even bursting and financial losses amongst jewelers have caused a loss of confidence in the purchase of Polynesian pearls and a price slump from 1999 on. Ongoing research may result in the replacement of shell nuclei with Bironite, an as yet little-known mineral composite produced in Australia. In the meantime, shell nuclei will certainly continue to be used for years to come…