Pearls traditionally belong to precious stones, they are widely used in jewelry and decorative finishing of accessories. However, in reality, this amazing work of nature has nothing to do with stones. Pearls are organic matter, the fruit of the life of some molluscs.
In nature, pearls can form in the shells of only one type - special bivalve shells of freshwater and marine pearl mussels that can secrete nacre. In fact, the formation of pearls is the reaction of the body of the mollusk to the ingress of a foreign body into the shell. It can be a grain of sand, a small parasite, or some other irritant. Then the folds of the mantle of the mollusk begin to secrete nacre, which envelops the foreign body in concentric circles, making it harmless to the shell.
Natural pearls can be round, pear-shaped or oval. In some cases, pearls of more bizarre outlines, the so-called baroque ones, are formed. The color of pearls can also vary significantly from completely white to pink, yellowish-bronze, and even almost black. The gem value of a pearl depends on its shape, size and color. The most expensive are round pearls of regular shape and clear, pronounced colors. Pearl size can vary from 3 mm. up to several centimeters. The largest is considered to be found in the Philippines in 1934. oval pearl Its size was 24 by 16 cm, and its weight reached 6.4 kg.
However, in reality, large pearls are not so common. This is due to the slow growth of the mollusk itself and the small size of the shells. Most "high-quality" pearls are 3 mm in size. up to 1cm. Pearls that have not reached the standard 3 mm are called beads or pearl dust. Sometimes the pearl is formed not in the folds of the mantle of the mollusk, but on the valve of the shell itself. Such formations are called "blister" or "bubble pearls". In the jewelry industry, it is much less valued, because, unlike traditional rounded pearls, blister pearls require significant processing before being inserted into jewelry.
Since the beginning of the twentieth century, pearls began to be grown artificially on an industrial scale. Basically, such pearl farms are created by Japanese specialists who have significantly improved the ancient Chinese art of growing pearls. To obtain perfectly round pearls, an artificially carved tiny nacreous ball is inserted into the pearl shell. Then the shell on a special pendant is placed back into the sea and removed again only after 7 years, resulting in large pearls of perfectly even rounded shape.
