Detection of gamma irradiated South Sea cultured pearls

It is very difficult to detect irradiated South Sea cultured pearls (SSCPs) at a low dose by gemological methods (e.g. optical transmission method, microscopic examination, UV fluorescence reaction, and so on). In this study, however, it was possible to distinguish between irradiated SSCPs from un-irradiated SSCPs by ESR analysis. We have analyzed the pearl nacre and nucleus by separating them for the purposed of providing information about the change of CO2 − radical as growing absorbed doses. And it was found out that the signal of CO2 − radical of the nacre is more distinct than the nucleus.