Culturing Tahitian Pearls
By Josh Humbert of Kamoka Pearls (KamokaPearls.com).
By Josh Humbert of Kamoka Pearls (KamokaPearls.com).
Tahitian pearls are cultured in lagoons surrounded by atolls in French Polynesia using the Pinctada margaritifera mollusk (pearl oyster).
Collecting the Baby Oysters
Oysters start their lives as free-swimming plankton in the lagoon. After three weeks of swimming, they begin to grow shells and search for a surface onto which they can attach. Farmers set out collectors during strategic times of year (usually corresponding to changes in the season) that offer ideal places for the young and vulnerable oysters to seek refuge and mature.
After around two and a half years the oysters are large enough to start producing pearls. This process is started by a graft, a painstaking procedure similar to surgery. A successful grafter uses sterile and razor-sharp tools, antibiotics, an eye for detail, and a very, very steady hand. The mantle of a living oyster is the organ that produces the splendid iridescence called nacre, for which pearls are valued.
Grafting The Shells
Grafting involves transplanting a small piece of mantle from one oyster to another. The graft tissue largely dictates the quality of the pearl. Donor oysters are usually chosen for the beauty of their colors, as their mantle creates the eventual color of the pearl.
Insertion of the Nucleus
The next step in the grafting process is the insertion of a nucleus, the six-to-eight-millimeter ball around which the pearl grows. The Japanese researchers who pioneered the grafting process discovered that the shell of a wild mussel in the Mississippi river basin had the appropriate density necessary for a pearl nucleus, and to this day most nuclei come from this unlikely mollusk. In recent years other nuclei types have been used, notably the very successful M.O.P. beads.
M.O.P. nuclei are carved from the shells of pearl producing oysters Pinctada margaritifera and Pinctada maxima.
The Oysters are then Tended for a Year and a Half
Immediately after the grafting operation the oysters are then suspended on long lines in the clear water of the lagoon for about a year and a half as the pearls inside them form and grow. Finally, the oysters are removed, and their pearls are gently extracted. A second graft is then performed, this time with a much larger nucleus that roughly corresponds to the size of the extracted pearl.
At the harvest of this second pearl a third graft of even larger proportions is sometimes performed. Although extremely rare, nuclei up to 18 millimeters in diameter are sometimes used. Unfortunately, every successive pearl sees the increasing age of the oyster and the subsequent decline in quality. This is why very large pearls of excellent are quality so rare.
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