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The largest pearl-bearing oyster is the marine Pinctada maxima, which is roughly the size of a dinner plate. Not all individual oysters produce pearls. In nature, pearl oysters produce pearls by covering a minute invasive object with nacre. Over the years, the irritating object is covered with enough layers of nacre to become a pearl.
Pearls are also obtained in commercial quantities from some species of the closely related winged oyster genus Pteria. Pearls are also produced from freshwater mussel species unrelated to pearl oysters. These freshwater species include Hyriopsis cumingii, Hyriopsis schlegelii, and a hybrid of the two species. At danger from the large demand for ...
By the 1840s, the export of the shells was as valuable as the pearls extracted from them; the nacreous shells were used to make mother-of-pearl buttons for clothing. In 1874, compressed air diving equipment made harvesting the oysters easier. By the early 1900s, some 200,000 to 500,000 oysters were being harvested annually. [10]
This species is commonly farmed and harvested for pearls, and there is general consensus that the quality of pearls from Pinctada margaritifera is the highest quality out of all the pearl oysters. Pearls form when a parasite or other irritant enters into the oyster and nacre is released by the oyster to coat the object, eventually creating a ...
There are two different color varieties: the Gold-lipped oyster and the Silver-lipped oyster. These bivalves are the largest pearl oysters in the world. They have a very strong inner shell layer composed of nacre, also known as "mother of pearl" and are important to the cultured pearl industry as they are cultivated to produce South Sea pearls.
A "mabe" (irregular) pearl can be grown by the insertion of an implant, usually made of plastic, under a flap of the mantle and next to the mother-of-pearl interior of the shell. A more difficult procedure is the grafting of a piece of oyster mantle into the gonad of an adult specimen together with the insertion of a shell bead nucleus.
Oysters and mussels reportedly contain 'disturbingly' high levels of fiberglass, which can cause skin, eye, and upper respiratory tract irritation.
Oyster farming is an aquaculture (or mariculture) practice in which oysters are bred and raised mainly for their pearls, shells and inner organ tissue, which is eaten. Oyster farming was practiced by the ancient Romans as early as the 1st century BC on the Italian peninsula [1] [2] and later in Britain for export to Rome. The French oyster ...