Fluorescence from Pearls and Shells of Black Lip Oyster, Pinctada Margaritifera, and Its Contribution to the Distinction of Mother Oysters Used in Pearl Culture

The fluoresence of pearls and shells of Pinctada margaritifera (black lip oyster) has been measured in order to distinguish the species of mother oysters which produce those pearls. A distinction is possible for pearls of P. margaritifera from those of Pinctada fucata and Pinctada maxima using a difference in the fluoresence spectra; this difference is caused by the presence or absence of porphyrin in pearls, respectively. However, the distinction between P. margaritifera and Pteria penguin, both of which have porphyrin in nacre, is difficult by measuring the fluorescence spectra. It is achieved by measuring the optical reflection spectra, since P. margaritifera shows a peculiar dip at 700 nm