一种新型醇酸树脂仿宝石制品的鉴定

Identification of a New Alkyd Resin of Gem Imitation

针对近期龙陵珠宝市场上出现一种商家声称“压制金珊瑚”的手串类饰品,采用常规宝石学测试、红外光谱法、拉曼光谱法、X-射线荧光光谱法、紫外-可见光谱法等方法对其材料属性、鉴定特征进行了研究,探讨其与同类材质的其他仿制品的差异。红外光谱及拉曼光谱测试表明此类饰品为醇酸树脂类塑料。其折射率为1.56(点测),密度约为1.235 g/cm^(3),硬度4~5,区别于其他塑料仿制品的显著特征是呈丝绢光泽,硬度较高,弹性及韧性极好,小刀切割有明显爆裂感,并产生碎块、粉渣。X-射线荧光光谱及紫外-可见光谱分析显示其金黄-黄褐色体色由Ti、Cr、Fe、Co、Cu等多种过渡性金属元素对光的选择性吸收共同作用而产生。因采用不同改性技术醇酸树脂类宝石仿制品可具有不同的物理性质及外观特征。除常规宝石学测试外,须综合运用红外光谱、拉曼光谱等测试其基团类型、分子结构及振动模式方能准确鉴定。

Recently,a new kind of gemstone with the trade name of"suppress golden coral"appears in Yunnan Longling jewelry market.Conventional gemological testing,Infrared spectrum,Raman spectrum,UV-visible spectrum,X-ray fluorescence spectrum methods are used to study the material properties and identification characteristics of the samples,and to discuss the difference between this one and other imitations of the same material.Infrared spectroscopy and Raman spectroscopy tests show that the jewelry is made of alkyd resin plastic.The refractive index is 1.56,the density is about 1.235 g/cm^(3),the hardness is 4~5.It is different from other plastic imitation of the remarkable characteristics for the silk gloss,high hardness,flexibility and very good toughness.Knife cutting has obvious burst feeling,and fragments,powder slag are produced.X-ray fluorescence spectrometry and UV-vis spectroscopy tests show that the golden yellow brown body color is produced by the selective absorption of various transitional metal elements such as Ti,Cr,Fe,Co and Cu.Alkyd resin gemstone imitations have different physical properties and appearance characteristics due to the different modification techniques.In addition to the conventional gemological test,the group type,molecular structure and vibration mode must be analyzed by infrared spectroscopy and Raman spectroscopy methods to get the accurate conclusion.