Identification Characteristic of White “Electro-Deposition” Freshwater Pearl

Recently, a kind of freshwater pearls being strong to very strong luster have appeared on the jewelry market in China, which are called "electro-deposition" pearls.For studying the identification characteristics of these "electro-deposition" freshwater pearls, the authors collected and tested the white freshwater pearl, bleaching freshwater pearl, and "electr-deposition" freshwater pearl samples by using the conventional gemmological methods, infrared spectrometer, scanning electron microscope and energy dispersive spectrometer.The results showed that the luster of white "electro-deposition" freshwater pearls was stronger than the others, and its refractive index and relative density were similar with white freshwater pearl.The ultraviolet fluorescence of white "electro-deposition" freshwater pearls was light blue, which was weaker than that of bleaching freshwater pearls.The strong reflected light and metallic colour of white "electro-deposition" freshwater pearls could be seen by the gem microscope.The scanning electron microscope testing result indicated that the surface layer of white "electro-deposition" freshwater pearls was anomaly bulge as sputtering distribution.Energy dispersive spectrometer testing showed that content of Ti element in the low-lying place of white "electro-deposition" freshwater pearls was 3.74%, and its content was positively correlated with the luster intensity, which can be used for identification characteristic.