There is no unified standard for the classification of pearls.Pearls A more practical classification scheme is a comprehensive classification based on cause and water area. The classification scheme is as follows: natural pearls,Pearls the natural parts of the natural pearl shells have lesions on their own, Pearls or they cannot expel invading external foreign bodies (such as sand, etc.). Due to their physiological functions,Pearls they will secrete nacre to change the lesions or foreign bodies. Wrapped up, Pearls it will form a crystal after a certain period of time. This crystal is called natural pearl. It includes: natural sea water beads: namely sea beads,Pearls which are pearls produced by marine shellfish. Natural freshwater pearls: pearls produced from freshwater mussels.
Cultured pearls: According to the physiological function of pearl shells to secrete pearls,Pearls pearls are implanted into small pieces of cells (or nucleus + cell small pieces) in the body of pearl shells. Pearls The pearls cultivated after a certain period of time are called cultured pearls. Including seawater cultured pearls and freshwater cultured pearls.
Artificial imitation pearls: made of plastic, glass,Pearls shells and other small balls as the core,Pearls and the surface is coated with a layer of "pearl semen".