Tahitian pearls, renowned as natural “black pearls”, originate exclusively from the South Pacific islands of French Polynesia. Cultivated from the black-lipped oyster, the mystical aura created by their lustrous black sheen and incredible size excite the imagination and make them particularly prized possessions. However, Tahitian pearls are not confined to black, but actually exhibit a wide spectrum of colors: peacock green, dark purple, yellowish green, brown, grey…endlessly varied by a vast array of overtones that have captivated the hearts of pearl lovers for centuries.
Widespread cultivation of Tahitian pearls started from the early 1960’s, when, due to dangerously rapid depletion, the Tahitian government prohibited the hunting of natural black-lipped oysters. Tahiti is the largest island in the Windward group of French Polynesia, located in the archipelago of Society Islands in the South Pacific Ocean. Tahitian pearl farms are not confined to Tahiti, but are widely distributed over numerous islands in the South Pacific.
Shallow lagoons surrounded by coral reefs, a clean and stable water flow, as well as sufficient nutrients and sunlight are all factors that characterize a unique living environment on these islands for the black-lipped oyster.
Tahitian pearl production today
For decades now, both pearl farmers and scientists have collaborated to hone the cultivation techniques of Tahitian pearls to such a point that the Tahitian pearl industry is now a significant feature of the economy of French Polynesia.
The most common species of oysters used to produce Tahitian pearls, the Pinctada margaritifera and the Pinctada mazatlanica, are the only oysters which produce naturally black pearls. Any black freshwater or Akoya pearls found on the market, have undergone a dying process.
Young Tahitian oysters are carefully reared in mesh submerged in environmentally protected and closed lagoons to avoid predation, and are retrieved from time to time for cleaning and examination. Black-lipped oysters can live as long as 30 years. At the age of about 18 months, the oysters are ready to be grafted.
The pearl graft must be carefully performed by a skilled technician. A piece of mantle tissue provided by a donor oyster is implanted into the host oyster’s gonad to act as the catalyst for the host oyster to secrete nacre. With it is inserted a bead made of mussel shell to act as the nucleus on which the nacre will be deposited. The mantel tissue needs to be chosen with great care as it will significantly influence pearl quality.
These oysters are not killed at harvest time. Healthy oysters that produce well can be used as hosts two or three times. As the bead inserted into an oyster that has already produced a pearl will then be the same size of the pearl that was extracted, larger pearls can be generated in the next growth cycle.
Tahitian Pearl Colour
A Tahitian pearl is distinguishable from other types of pearls by darker colors, a metallic shine and deep overtones of color.
The color of Tahitian pearls is mainly generated by the mantle tissue with which it is nucleated, but the living environment of the oyster may also influence the nacre formed, leading to a wide variation of Tahitian pearl colors. No black-lipped oyster will produce exactly the same color.
The main color groups of Tahitian pearls are dark black, peacock (greenish black), pistachio (greenish gray), aubergine (purplish black), champagne (yellowish gray) and some other rarer colors.
Tahitian Pearl Size
As with all types of pearls, a larger Tahitian pearl, if it is of high quality, will be of higher value. Tahitian pearls are generally larger than the pure-nacre freshwater pearls. Average sizes range between 8mm and 14mm, but rarely beyond 16mm, and the price will increase exponentially when the pearl is of a rare large size.
Tahitian Pearl Shape
Only about 5% of harvested Tahitian pearls are perfectly round, and only 1-2% of the harvest will be of sufficient quality to be considered gems. Tahitian pearls of spherical shape are more valuable, and like other types of pearls, the other common shapes of Tahitian pearls are the off-round, drop and button.
One unique subset of Tahitian pearl types, is characterized by rings or circled grooves which extend all the way around the pearl body. It is a favorite amongst some jewelry designers and collectors because this particular circled/ringed shape tends to reflect extra light and shine more brilliantly.