How is a pearl made??

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  • 1 decade ago
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    All bivalves have the ability to create a pearl. This includes freshwater mussels and saltwater mollusks or oysters. Even clams can create pearls. The largest pearl ever found is the Pearl of Allah; a giant clam pearl.

    There are two answers to your question. One is the process from which natural pearls are formed, and the other is the process of culturing pearls. In today's jewelry market only cultured pearls are readily available. Natural pearls are not commercially harvested and have not been on a large scale for nearly 100 years.

    A natural pearl forms when an invader (not a grain of sand - that is an urban legend) invades the shell. This is most often a parasite. The parasite burrows through the periostracum layer of the shell (the outer portion), and penetrates the mother of pearl and mantle of the animal. The parasite may become trapped and die.

    The mantle tissue of the mollusk contains cells known as epithelial cells. These cells are responsible for layering the inner shell with nacre, or mother of pearl. This is the same substance of which a pearl is composed .

    The mollusk’s natural, self-preserving reaction to this invader to envelop it with a thin film known as a pearl sac. This sac has the same epithelial cells lining the inside. Once the sac has enveloped the intruder the cells begin to produce nacre. The nacre is laid down in platelets of aragonite which are held together with a natural 'glue' known as conchiolin. A natural pearl forms.

    A cultured pearl is also a genuine pearl. The difference is that a pearl farmer has given Mother Nature a helping hand.

    There are two general methods of pearl farming; saltwater pearl farming and freshwater pearl farming.

    In all saltwater perliculture a bead of rounded mother of pearl is used. The shell is coaxed open very slightly, a small incision made to the gonad of the host, and the bead is inserted. As there are no epithelial cells within the gonad, it is necessary to insert a small piece of mantle tissue from a donor mollusk into the gonad, next to the bead, with the outer edge against the bead (the outer edge has the epithelial cells). The process of pearl formation is the same as previously described.

    Freshwater perliculture is different in that a bead is not used. Only the small piece of mantle tissue from a donor mussel is used. This tissue is not placed in the gonad. It is placed in multiple incisions in the host mussel. Most freshwater mussels are implanted with 12 to 16 pieces of mantle tissue on either side of their valve.

    Because freshwater perliculture does not use a bead, except in rare circumstances such as CBSB (coin bead, circular bead) grafting, freshwater pearls are rarely round.

    If you would like to see a video of the actual seeding process, there are several at the YouTube channel below which show both saltwater and freshwater pearling operations.

    http://www.youtube.com/profile?user=PearlParadise

  • Anonymous
    1 decade ago

    Uh, clams don't make pearls, Oysters do. They do it by secreting the same material that coats the inside of their shells, to reduce the irritation of the foreign object. It's a mineral, but produced by biological processes.

    - The Gremlin Guy -

  • 1 decade ago

    A grain of sand gets lodged in a clam. Over time the clam rebuilds layers upon layers on top of it because the sand bothers the inside of the clam, so it tries to make it smooth. That is what makes a pearl

  • 1 decade ago

    Why are you making a pearl?

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  • 1 decade ago

    A bit of shell or sand inside of a clam or oyster gets coated with multiple layers of a secretion which hardens.

  • 1 decade ago

    um... in a clam over about 10 years a grain of sand is tranformed into what now is a pearl... um there is like Black White and Pink kinds!

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