Consideration for nacre thickness of nucleated cultured pearls

Abstract

Nowadays pearls in the market are almost cultured pearls. Especially many of nearly round pearls are nucleated cultured pearls and the nacre thickness is an important quality factor. By Soft X-ray photograph, the internal structure and the nacre thickness can be examined. However, each of pearls formed by various kinds of mother oyster or mussel shows different size and possesses a different size of nucleus. Then I invested how the nacre thickness of various pearls should be graded. In addition,I consider the nacre thickness which is needed for as pearl in gem.