Nålperla

Nålperla, also known as needle pearl, is a type of pearl that is formed by the irritation of the mantle tissue of a pearl oyster. This irritation can be caused by the insertion of a small piece of foreign material, such as a grain of sand or a fragment of shell, into the oyster's mantle. The oyster responds to this irritation by secreting layers of nacre, the same material that makes up the oyster's shell, around the irritant. Over time, these layers accumulate and form a pearl.

Needle pearls are typically small, ranging from 4 to 10 millimeters in diameter, and are often irregular in shape. They are valued for their unique appearance and are often used in jewelry. The process of creating a needle pearl is relatively simple and can be done by inserting a small piece of material into the oyster's mantle. However, the success of this process can vary, and not all oysters will produce a pearl.

Needle pearls are not to be confused with cultured pearls, which are created by surgically inserting a piece of mantle tissue into the oyster's mantle. Cultured pearls are typically larger and more uniform in shape than needle pearls.