Pearls are perhaps the most unusual of all gemstones. It is of animal origin, not forming in the bowels of the earth, like a diamond or emerald, but in the shells of mollusks. At the same time, for a long time, the process of the emergence of pearls was shrouded in legends.
The ancient Greeks believed that the tears of mermaids turned into pearls. In the Middle Ages, people sincerely believed that pearls are the tears of orphans that angels hide in shells. The inhabitants of Ancient Russia thought that pearls were mollusk eggs, and that there were female and male shells. In Karelia, a poetic legend has arisen that a pearl spark is born in the gills of a salmon. On a sunny day, the fish lowers it into an open shell, where a beautiful pearl is born from it.
A scientific explanation of the origin of pearls appeared only at the beginning of the 19th century. The real process of pearl origination turned out to be no less interesting and poetic than the one described in the legends.
It happens that a grain of sand or a parasite enters the ajar shells of the shell, which irritates and injures the delicate surface of the mollusk mantle. To protect itself from pain, the mollusk begins to intensively produce nacre, enveloping a foreign body with it. This process exactly repeats the actions of the mollusk during the formation of the shell.
By creating a pearl, the mollusk relieves itself of the suffering caused by a foreign object. By hiding it inside a smooth ball, it thus relieves irritation. Thus, in the middle of the pearl, you can always find the so-called "crystallization center", which is, in fact, the embryo of the pearl. But it also happens that a pearl is formed around a gas bubble, a liquid droplet or a piece of tissue of the mollusk itself. Then, in the process of pearl formation, the embryo gradually decomposes, and it may seem that it has arisen by itself.
The shape of the pearl depends on where the foreign object has hit. If it happens to be close to the surface of the shell, then its mother-of-pearl layer literally grows together with the shell's mother-of-pearl, forming an irregular pearl called a "blister". A distinctive feature of the blister is the absence of a mother-of-pearl layer in the place of its attachment to the shell. But if an object falls into the mantle of a mollusk, a pearl of perfectly regular shape grows. Sometimes pearls are formed in the muscles, then it forms an unusual, sometimes - a very bizarre shape.
Molluscs that have the ability to create pearls are called pearl mussels. They can be both river and sea. At the same time, freshwater pearls are many times cheaper than sea pearls. It is much smaller, not so regular and not nearly as shiny. But it is much stronger.
Initially, people dug for pearls by diving for pearl shells to a depth of 20 meters and risking being attacked by sharks. However, having learned how pearls are formed, they learned to grow it artificially.
Pearls are grown in the following way: after opening the shells, foreign bodies are placed under the mantle of the mollusks, most often mother-of-pearl beads. Then the sink is placed in a special reservoir. It takes 3 years to grow a sea pearl, a river pearl grows in 2 years. Pearls grown in this way are called cultured pearls. It is he who is most often used in the manufacture of jewelry.