An Akoya cultured pearl is not an artificial or synthetic pearl; it is produced by a pearl oyster and by the normal processes of pearl growth. The only difference between a natural pearl and the cultivated variety is that a nucleus has been inserted into the oyster to enable the pearl to have a good start. It ensures a larger and more evenly shaped pearl is produced. Pearls that were taken from the water in ancient times were natural. Today naturally occurring pearls are very, very rare.