Just as an aside, do the molluscs die for the pearls to be harvested? And if so does this make Ralph as bad as Basso
sorry feeling naughty
Found this on Yahoo
The answer depends on the type of pearl farm. There are four common commercial types of farms; freshwater pearl farms, akoya pearl farms, Tahitian pearl farms, and South Sea pearl farms.
Freshwater mussels (not oysters) produce up to 32 pearls at a time. They are implanted with up to 16 pieces of mantle tissue on either side of their valve. When these pearls are harvested, 2 to 6 years later, the mussel does not necessarily die. It may be returned to the water to grow regenerated pearls (or "keshi" pearls), or bead-nucleated freshwater pearls.
When the mussel has outlived its usefulness, the meat it used as fertilizer (it is not eaten), and the shell is used for art and pearl-powder products.
A freshwater pearls are harvested by opening the shell very slightly, cutting open the pearl sac, and removing the pearl (if the shell is to be reused). Otherwise the shell’s valves are completely separated with a large knife and the pearls are pulled from the mantle where they are grown.
Akoya oysters are saltwater and they are only used once. Unlike freshwater mussels, akoya oysters are nucleated with round beads composed of mussel shell. This bead is placed inside the oyster's gonad.
They die when their pearls are harvested. Each shell can produce up to 5 pearls at a time, although most farmers only nucleate with one to two beads. The shell is currently used in China mainly for button production. The adductor muscle of the oyster is eaten, and the guts are disposed of.
Akoya pearls are harvested by completely separating either valve and pulling the pearl from the gonad.
Tahitian oysters are saltwater and are nucleated in much the same way as the akoya. The difference is that each oyster can only handle one bead at a time. The oyster does not necessarily die upon harvest, however. Another bead can be placed into the existing pearl sac within the gonad. The shell can be returned to the water, and another pearl can be produced. This process can be repeated up to three times.
When the shell has outlived its purposed, it may be returned to the water to live out its days, or its meat may be harvested. The adductor muscle is eaten. The shell is used for mother of pearl products.
A Tahitian pearl is harvested much in the same way it is nucleated. A technician will open the shell very slightly, create a small incision in the gonad, and remove the pearl. A second bead the same size as the harvested pearl can be replaced in the gonad.
South Sea pearls are saltwater and are harvested in the same fashion as Tahitian pearls - the oyster does not necessarily die. They grow only one pearl at a time, can be re-nucleated. If the oyster is killed the adductor muscle is eaten and the shell is used in mother of pearl products.