Pearl, unlike gemstones or precious metals, is a kind of lively gem. A natural pearl forms when an irritant, such as parasite or a piece of sand, accidentally enters the body of a particular species of oyster, mussel or clam and cannot be expelled. As a defense mechanism, the mollusk secretes a smooth, crystalline fluid, called “nacre” (the same secretion it uses for shell-building, composed mainly of carbonated calcium), to coat the intruder. As long as the irritant is present, the mollusk continues to add a layer upon a layer of nacre on the irritant until a lustrous pearl is formed.
A cultured fresh water pearl, which is grown in a clam undergoes exactly the same process. The only differentce is that the irritant is a surgically implanted piece of mantle tissue. To culture fresh water pearls, skilled technicians slightly open a host clam’s shells up to 1 - 1.2 cm, cut small slits into the mantle tissue inside both shells, insert a small piece of epthelial membrane (the lip of mantle tissue) from another clam into those slits, and using a fine needle to shape it into round. After implanting, it takes five to seven days for a host clam to cover an irritant with its own tissue and 10 days later it begins producing centric layers of nacre. Tendering pearl-bearing clams is a continuous process aiming at smoothly developing the pearls to minimize blemishes. The pains-taking process can last four to five years long.
Apparently, in fresh water clams, the insertion alone is sufficient to start nacre production. No artificial nucleating bead is needed. Therefore cultured fresh water pearls are composed entirely of pure nacre, making them “real” pearl, just like their natural fresh water and natural salt water counterparts.
A cultured fresh water pearl, which is grown in a clam undergoes exactly the same process. The only differentce is that the irritant is a surgically implanted piece of mantle tissue. To culture fresh water pearls, skilled technicians slightly open a host clam’s shells up to 1 - 1.2 cm, cut small slits into the mantle tissue inside both shells, insert a small piece of epthelial membrane (the lip of mantle tissue) from another clam into those slits, and using a fine needle to shape it into round. After implanting, it takes five to seven days for a host clam to cover an irritant with its own tissue and 10 days later it begins producing centric layers of nacre. Tendering pearl-bearing clams is a continuous process aiming at smoothly developing the pearls to minimize blemishes. The pains-taking process can last four to five years long.
Apparently, in fresh water clams, the insertion alone is sufficient to start nacre production. No artificial nucleating bead is needed. Therefore cultured fresh water pearls are composed entirely of pure nacre, making them “real” pearl, just like their natural fresh water and natural salt water counterparts.
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