Probably, the first person who has found in a sink of an oyster the sparkling pearl, counted the find as miracle or gift of gods. But over time people learned to grow up this beauty. Unlike jewels, fossil minerals, natural pearls – a renewable product which make industrial methods. 
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Unfortunately, in cultivation of a pearl anything magic is not present. Pearls – result of resistance of a live organism to external damages. The processes similar to formation of pearls, occur in lungs of the person struggling with tuberculosis.
To grow up a beautiful pearl, to an oyster put damage and put inside a foreign matter. In reply to such barbarous intervention the mollusk tries to isolate itself from an extraneous subject. Eventually, it can even вытолкнуть it outside but before the oyster will be prepared for it, passes some years.
The natural pearl is formed as a result of casual transfer of cages a cloak epiteliya in connecting fabrics where they, breeding, form the closed cyst called by a pearl bag.
«We cannot wait for favor by nature» therefore on farms into a mollusk body surgical methods enter cloak fabrics together with sink slices then provide oysters to itself. In a year the pearl adds no more than 0,5 mm in the sizes.
After an inoculation round a transplant formation of a pearl bag begins. The mollusk slowly turns a kernel a layer an epiteliya, and then covers a pearl bag with layers of a polymorphic carbonate of calcium. The pearl so is born.
Its nacreous cover is formed by the cells of aragonite fastened by albuminous and chitinous organic layers. The thickness of each layer of nacre is measured by micron shares.
Minimum admissible for commercial use thickness of nacre – 0,8 mm. On formation of such layer it is required more than a year. Mechanisms of formation of a nacreous cover of a pearl were not studied until recently. The French researchers became interested in them.
The traditional round form of pearls and nature of natural defects allow to assume that the pearl rotates in a mollusk body in process of growth. For check of this hypothesis researchers implanted tiny magnetic balls round which pearls were formed in a pearl oyster of Pinctada Margaritifera.
Scientists watched pearls development by means of the difficult magnitometrichesky system developed specially for experiment. Magnitomera fixed the slightest changes of provision of magnets in mollusks.
As a result of supervision researchers defined that any time (24-40 days) after an inoculation of a pearl are motionless, but then start to rotate continuously throughout the entire period of growth, doing a complete revolution round its pivot-center approximately in 4 hours of 43 minutes with average angular speed of 1,27 degrees a minute.
According to authors of the research which results were published by the magazine «Open science of Royal society» (Royal Society Open Science), they managed to slightly open for the first time one of secrets of the nature and to demonstrate, how such difficult structures, as pearls are formed.