The Pinctada Margaritifera Oyster lives naturally in the Polynesian lagoons. Hermaphroditic, it releases both oocytes and spermatozoa into the water at certain times of the year. Once fertilised, the eggs give birth to larvae: the spat. These need to settle somewhere safe from predators to grow, such as braided plastic wire supports that we use.
Young oysters are removed from the wire supports and moved to underwater breeding stations. The oyster’s growth is closely monitored to ensure they remain healthy and safe from natural predators such as fish, stingrays, and octopi.
The secret to healthy oysters is to keep them clean by removing any shells, mollusks, and seaweed that continually attach themselves to an oyster’s shell. Such parasites compete with the oyster for food, weigh them down, and prevent them from opening correctly to filter the sea water for nutrients. Regular cleaning is vital, a process undertaken three or four times a year, where the oysters are taken briefly from the water, carefully cleaned, and immediately returned to the breeding stations.
After three long years, the oyster will have grown to a diameter of between 10-12 centimeters (4-5 inches), by which time they are ready for grafting.
Young oysters are retrieved, removed from the wire supports and moved to underwater breeding stations. The oyster’s growth is closely monitored to ensure they remain healthy and free from natural predators such as fishes, stingrays and octopus.
The secret to healthy oysters is to keep them clean by removing any shells, molluscs and seaweed that continually attach to the oyster’s shell. Such parasites compete with the oyster for food, weigh them down and prevent them from opening correctly to filter the sea water for nutrients. Regular cleaning is vital; a process undertaken three or four times a year, where the oysters are retrieved briefly from the water, carefully cleaned and immediately returned to the breeding stations.
After three long years, the oyster will have grown to a diameter of between 10-12 centimetres (4-5 inches). They are now ready for grafting.
Grafting for cultured pearls is a process similar to the one to produce a natural pearl, whether the foreign body is a grain of sand, a parasite, or a nucleus introduced by hand, if it is accepted by the oyster it will eventually become a pearl. Grafting is a high-skill task and must be done quickly to maximize the chances of success.
The grafter starts by placing a tiny piece of tissue from a donor oyster’s mantle inside the oyster. He then inserts a spherical “nucleus” fashioned from the shell of a freshwater mussel, which the oyster will automatically try to reject. Inserting tissue from a donor oyster has several functions:
cells from the oyster tissue develop around the nucleus, forming a pearl sac, inside which the pearl will be formed;
The mantle tissue plays an important role in determining the quality of the resulting cultured pearl;
The pearl sac regularly secretes pearl material around the nucleus. Extensive research has shown that the best mussel shells from which to make the nucleus come from a freshwater variety found only in American Mississippi River.
Two whole years are needed to allow the oyster to produce a high quality pearl. During this time, pearl care is devoted to the attention of the oysters. If a pearl is harvested too early, its quality will be poor because the ultra-delicate bag will not have had enough time to train and develop in the best conditions.
A harvest is the result of 5 long years of work, discipline, and above all patience.
The harvest is done in front of the grafters who can judge the work they’d done two years previously. They measure their results and can act on their gesture and technique if necessary.
Then, if the mother oyster is in good health and the grafter judges the harvested pearl as being of good quality, the oyster is grafted once more without waiting. The extracted pearl is simply replaced by a nucleus of similar size. This time, the presence of the graft is not necessary.
TAKING CARE OF YOUR PEARLS
HOW FRAGILE ARE PEARLS?
On a scale of 1 to 10, pearls are classified as 3 on the ‘Mohs’ scale of hardness, whereas diamonds rate as 10, being the hardest mineral in existence. Compared to a diamond, the pearl is therefore relatively soft and can be scratched by a gemstone. Ideally, pearls should be stored separately in a soft pouch. Pearls are made of calcium carbonate with an outer covering of aragonite. They are sensitive to acids and other corrosive substances, so should never be exposed to household substances, perfumes, or other acidic materials. Pearls should always be removed when swimming in a chlorinated pool.
CAN PEARLS DIE?
Pearls can fade and crack if exposed to extreme heat, or kept for years in a dry atmosphere such as in a safe.
WHAT IS THE BEST CARE FOR PEARLS?
Pearls require relatively little care. They ask only to be worn from time to time so that they can be hydrated by direct contact with the skin. Simply wipe pearls with a soft cloth to preserve their beauty and gloss, or alternatively wash them in clean seawater.