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| 1. The Formation of Fresh Water Pearls |
Pearls, unlike gemstones or precious metals, are grown by
live creature. 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 of nacre upon a lay of
nacre on the irritant until a lustrous pearl is formed.
A cultured freshwater pearl, which is grown in a mussel, undergoes
the same process. The only difference is that the irritant is
a surgically implanted piece of mantle tissue. To culture freshwater
pearls, skilled technicians slightly open a host mussel's shells,
cut small slits into the mantle tissue inside both shells, and
insert small piece of epithelial membrane (the lip of mantle
tissue) from another mussel into those slits. After implanting,
it takes five to seven days for a host mussel to cover an irritant
with its own tissue and 10 days later it begins producing centric
layers of nacre.
Apparently, in freshwater mussels, the insertion alone is sufficient
to start nacre production. No mother -of -pearl beads are needed.
Therefore cultured freshwater pearls are composed entirely of
nacre, making them "real" pearl, just like their natural
freshwater and natural saltwater counterparts. |
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