farming has produced almost all of the Pearls being sold around the world today. Commercial production has been developing since 1916. The benefits of Pearl farming are the large amounts of Pearls that can reliably be created and the control over the conditions that produce the Pearls. The downside of Pearl farming occurs when the sea beds used for propagation become polluted, as has happened in Japan, for instance, where formerly productive Lake Biwa was the principal source of freshwater Akoya Pearls.
Many attempts were made to cultivate Pearls in oysters, in particular, before a system for Pearl farming was developed that worked well. This system originated in Australia and was brought to Japan and merged with similar attempts there to create Pearl farming methods that are still in use today.
In the beginning, oysters were collected from the sea, but soon Pearl farmers were breeding their own by collecting sperm and eggs from the best oysters on the Pearl farm. After a few weeks of larval stage, Pearl farmers collect them and place them into special collectors.
When the larvae become baby oysters, they are shifted to a nursery area of the Pearl farm, where they remain growing for one to two years. Some species need further care, with periodic algae removal. Then begins the true purpose of Pearl farming: nucleation.
is opened by hand and surgically implanted with a bead nucleus – a small disc or ball that often is wrapped partially with a piece of tissue from a donor mollusk. In response to the irritation of the implant, the mollusk begins laying down a series of layers of nacre
over the object. The nacre buildup is what ultimately forms the Pearl, giving it the iridescence
that is prized by jewelers and collectors.
Not every implantation in Pearl farming is successful. Often the oyster or other mollusk rejects the nucleus, or can sicken and die. The Pearl farmer waits a few weeks to see how each is doing before moving the healthy ones into nets or cages, in a sort of rack system, where they are tended for months to years while the Pearls are forming.
Because of the spherical orb armature that is implanted, the resultant Pearl most often takes on a round shape, which is valuable for stringing and using in necklaces and bracelets. Some Blister Pearls are grown on the inside of the shell, ending up with one flat side, lending itself well for use in rings, pendants and brooches.
Pearl farmers can grow more than one Pearl in a mollusk, especially in the freshwater mussels where no beads are used. Instead, bits of mantle tissue are inserted, which can be arranged on each valve or side of the mollusk in series of up to sixteen or so slits per valve. Because of the lack of a round bead, these Pearls take on a more asymmetrical appearance.
Cultured Pearls grown in Pearl farming can be x-rayed to determine whether they are farmed Pearls, as the bead nucleus will show up in the x-ray. Any modern Pearls can be assumed to be cultured. After collecting the Pearls from the mollusks, the Pearl farmer washes and dries them, then sorts them, before selling them to people who deal in Pearls or make jewelry with them.