Black pearl is a kind of bronze pearl, which belongs to a very valuable jewelry variety. Symbolizing the crystallization of the most difficult years, it is called the most painful tear of the mother shell, which is precious after suffering. Before the black-nucleated South Asian pearls were successfully put on the market, the only black pearls available for sale were rare and very expensive natural black pearls, or faded Japanese nucleated akoya pearls dyed black with silver nitrate.

There are also a few imitation black pearls. In the past 30 years, the pearl culture in French Polynesia has developed successfully. 1976, American Gemological Institute recognized the cultured black pearls produced in Tahiti as "cultured pearls with natural colors".

The formation of pearls

Pearls are hard and smooth products produced by mollusks (mainly oysters). Physical Properties The unique luster of pearls is caused by the reflection and diffraction of light on these transparent pearl layers. The thinner the nacre, the more beautiful the luster. The fluorescence of some pearls is formed by the constant refraction of incident light by different nacre layers.

Generally speaking, pearls are white, sometimes with beige or pink luster, and some pearls are yellow, green, blue, brown or black. Black pearls are particularly expensive because they are rare. Pearls are mainly the products of some petaloid mollusks. Epithelial cells peculiar to these animals secrete calcium carbonate, mainly aragonite and calcite combined by conchiolin. This mixture is called pearlescent.

The above contents refer to Baidu Encyclopedia-Pearl