What is black pearl in oyster?

A black pearl is a type of pearl that comes from certain species of oysters, specifically the black-lipped oyster from the South Pacific. They are also known as Tahitian pearls, as they are commonly found in French Polynesia.

Black pearls are made from the same process as other pearls; they form when irritants, such as grains of sand or small pieces of tissue, get inside the oyster and irritate the mantle, the tissue that lines the inner shell. The oyster then secretes layers of nacre, a combination of calcium carbonate and protein, around the irritant to protect itself. Over time, these layers build up to create a lustrous, unique pearl.

Black pearls are prized for their dark, rich colors, which range from deep charcoal to metallic green to iridescent peacock blue. The color of the pearl is determined by several factors, including the color of the oyster's outer shell, the water temperature, and the amount of sunlight the oyster receives.

Black pearls are highly valued in the jewelry industry, and their rarity makes them more expensive than other types of pearls. They are often used in high-end necklaces, earrings, and other items of jewelry.