HOW PEARLS ARE HARVESTED

Early on, pearl cultivation depended entirely on wild oysters. Later you'll learn that, in some cases, the same applies today. But modern pearl cultivation has become more selective.

In Japanese pearl cultivation, scientists have isolated strains of oysters that possess superior pearl-producing qualities. These selectively-bred oysters produce pearls of exceptional lustre and color clarity.

In a process referred to as "nucleation," also called "grafting" or "seeding," highly skilled technicians carefully open live pearl oysters, and with surgical precision make an incision in the oyster's body. Then, they place a tiny piece of "mantle tissue" from another oyster into a relatively safe location. Then, they place a small round piece of shell, or "nucleus," beside the inserted mantle tissue. The nucleus is a mother-of-pearl bead made from an American freshwater mussel. The cells from the mantle tissue develop around the nucleus forming a sac, which closes and starts to secrete nacre, the crystalline substance that forms the pearl.

The nucleated oysters are then returned to the sea where, in sheltered bays rich in nutrients, they feed and grow, depositing layer after layer of lustrous nacre around the nuclei implanted within them. The oysters are given the utmost care during this time, while suspended in the water, from the rafts above. Technicians check water temperatures and feeding conditions daily at various depths, moving the oysters up or down as appropriate. Periodically, the oysters are lifted from the sea for cleaning and health treatments. Seaweed, barnacles and other seaborne organisms that might interfere with their feeding are removed from the oysters' shells. The shells are also treated with medicinal compounds to discourage parasites.

Over time, after many months of growth and care, the oysters are ready for harvest. Those that have survived the many perils of the sea are brought ashore and opened. And then, when everything has gone well, a beauty is revealed -- the result is a lovely, lustrous and very valuable cultured pearl.