Pearl is the only gemstone that is of animal origin: it is formed not in the earth, like diamonds or emeralds, and in the shells of bivalves.
Where inside of the shells is taken pearls? In Ancient Greece believed that this hardened tears of mermaids. In the Middle ages believed that the angels hide in the shells of the tears of the orphan and the innocent downtrodden, and they turn into pearls.
In fact, the pearl is the fruit of the labors of mollusk self-defense! It occurs when the inside of the shell hits a foreign object or a parasite, irritating delicate body of a mollusk. Get rid of the foreign body clam can't, and so he is protected from the stranger, enveloping his layers of special substances. He does it exactly the same as in the formation of his shell.
The inner layer of the shell produced by the mantle of the mollusk, is a pearl. perl - pearls, mutter - mother; Perlmutter - "mother of pearl"). If you find a river or the sea shell of the bivalve mollusk, consider its inner side. You will see that it is covered with a layer, casting a beautiful glow. This is mother of pearl.
The inner surface of the shell
When the sink gets a foreign object such as a grain of sand or a parasite, the mantle begins to envelop the uninvited guest nacre layer by layer. And pearl is formed. Thanks to her clam gets rid of the inconvenience, which causes her foreign object. Having immured him in a smooth carbonate ball, shellfish reduces friction, reduces irritation.
Thus, in the center of the pearl there is always a center of crystallization, the germ of a pearl. But it also happens that a foreign object in the center of the pearl is missing. In this case, the seed for the formation of pearls can serve as a gas bubble, a drop of liquid or a piece of tissue of the mollusk in the formation of pearls it gradually decomposes.
The form of growing pearls depends on where he got it Bud. If pearl pouch is located at the surface of the shell, mother-of-pearl layer pearl merges with mother of pearl shell and forms an irregular pearl blister. The blisters at the site of attachment missing mother-of-pearl layer. If the bag will be in the mantle of the clam, pearl grows the correct form. Pearls are formed in the muscles or in the adjacent parts are wrong, often very intricate shapes.
The education bubble bag in the shell of a bivalve mollusk, a pearl
First, cells of the mantle begin to envelop alien body outer film forming around him
pearl SAC, which is pressed into the tissues of the animal. Inside pearl bag first released
little organic matter, then the calcium carbonate crystals in the form of prismatic aragonite and, finally,
aragonite in the form of lamellar layer (nacre).
A group of mollusks that can form pearls, called pearl.
Pearl mussels are freshwater and marine.
Freshwater or river, the pearl is the most versatile. It has long been used to decorate a peasant outfits and dresses noble ladies. Freshwater pearls thousands of times cheaper than the sea, as it is produced easier and faster; in addition, freshwater pearl larger marine and able to grow up to 20 pearls. Freshwater pearls are smaller marine has a less correct form and less shiny. But freshwater pearls stronger marine and more resistant to abrasion. Freshwater pearls has the largest share of pearling in the world.
Necklace of freshwater pearls
The highest quality pearls give marine shellfish species of the genera pinched (Pinktada) and peri (Pteria). They usually form a dense settlement banks, which are located at a depth of 10-15 m
At first people was extracted pearl diving for shells-pearl. Fishing pearl diver has more than 4 thousand years. It is very difficult and dangerous, because the diver must dive to great depths (usually up to 20 m without any accessories, armed only with a knife, to remain there for a sufficient time (usually one and a half minutes)to collect as many shells and make up to 30-40 dives per day! In addition, in sea diver sharks lurk.
Now that you know how pearls are formed, people learned to grow pearls artificially. This technology was invented by a Japanese researcher Cochiti Mikimoto in the 90-ies of the 19th century. He created the first company in the cultivation of pearls. Pearls are cultivated: opening sash shell, under the mantle of the pearl oyster introducing a foreign body, for example, a tiny bead or the bead of natural nacre. Then the sink is placed in a special reservoir, which create ideal conditions for living mollusks. To grow one good marine pearl, required 3 years, river - up to 2 years.
The thus grown pearls called cultured. Almost all pearls used in jewelry (90%), is cultured. In its properties it is no different from natural pearls, and is several times cheaper, despite the fact that not all cultured pearls meet quality standards - in this case a lot of marriage.
The main suppliers of cultured pearls are China and Japan, to a lesser extent Australia and Polynesia