白色“电镀”淡水珍珠的鉴别特征

Identification Characteristic of White“Electro-Deposition”Freshwater Pearl

近几年,中国市场上出现了一种强至极强光泽的淡水珍珠,业内称之为"电镀"珍珠。为有效鉴别该"电镀"珍珠,以白色淡水珍珠、常规增光漂白淡水珍珠和白色"电镀"淡水珍珠为研究对象,采用常规宝石学测试、红外光谱、扫描电子显微镜及能谱仪测试手段进行分析,结果发现,白色"电镀"淡水珍珠的光泽普遍强于白色淡水珍珠和常规增光漂白珍珠,前者的折射率和相对密度与白色淡水珍珠相当;白色"电镀"淡水珍珠的紫外荧光显示为浅蓝色,弱于常规增光漂白淡水珍珠;显微放大观察,白色"电镀"淡水珍珠表面反射光强,呈单一金属色,佩戴磨损后呈不规则斑状分布。扫描电子显微镜的测试结果显示,白色"电镀"淡水珍珠表面可见明显的不规则凸起,呈溅射状分布。能谱仪测试显示,白色"电镀"淡水珍珠低洼处Ti元素的质量分数可高达3.74%,这可作为"电镀"珍珠的鉴定依据之一,且其光泽强度与Ti元素的质量分数呈正相关。

Recently, a kind of freshwater pearls being strong to very strong luster have ap-peared 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 welectr-depositionw freshwater pearl samples by using the conventional gemmological methods, infrared spectrometer, scanning electron microscope and energy dispersive spectrome-ter. 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 re-flected light and metallic colour of white ielectro depositionw 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 Tielement 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 char-acteristic.