Pearl
This is the only stone that has an animal origin. How does it appear?
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The walls of the mollusk shell are covered inside with its mantle with small nerve endings. When the smallest foreign body gets inside, for example, a grain of sand, the nerve endings immediately react. A substance begins to be released - mother-of-pearl. So gradually, from a small pearl grain, over several years, a pearl is produced.
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There are different types of pearls:
* Natural sea,
* Natural freshwater,
* Cultured marine (with human participation),
* Cultured freshwater (with human participation).
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Natural pearls grow much more slowly and are then found on the market much less often, and their cost is higher.
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Do you have pearl items in your jewelry wardrobe?