A pearl is an ulcer that is formed when an irritant, such as a parasite, enters an oyster, who responds by coating it with nacre (a crystalline substance that gives pearls their luster). Stress is what prompts an oyster to secrete nacre (just like stress worsens human ulcers).
Because pearls naturally form in only one in 10,000 oysters and because the creation of a pearl can take up to three years, pearl-makers have devised a process called “culturing,” or cultivating, that allows them to exploit oysters faster and cheaper.
Culturing involves surgically opening each oyster shell and inserting an irritant in the oyster. Freshwater pearls are cultured by inserting another oyster’s mantle tissue. Saltwater pearls have beads and another oyster’s mollusk tissue inserted. Fewer than half of the oysters may survive this process.
Cultivators further stress the oysters by suspending them in water in a cage, washing their shells, moving them around in different waters, and raising and lowering their cages to subject them to changing water temperatures.
After the pearls are extracted from the oysters, one-third of oysters are “recycled” and put through the culturing process again. The others are killed and discarded.
For those concerned about the environment, there is another reason to avoid pearls. Aquaculture has contributed to destruction of natural pearl oyster beds from pollution and overharvesting.
Of course, with so many modern pearl imitations, as well as other kinds of jewelry, it’s easy to do without pearls.