重晶石质玉(处理)的宝石学特征

Gemmological Characteristic of Barite Jade(Treated)

笔者收到由客户委托待检测的样品(客户称为“青花玉”),采用常规宝石学测试、偏光显微镜,X射线粉末衍射仪、红外光谱、拉曼光谱、扫描电子显微镜及X射线能谱分析等测试方法对该类样品进行了测试研究。结果显示,该样品的折射率为1.63~1.64(点测),相对密度为4.17~4.20,在长波紫外荧光灯下浅蓝色部分显示弱荧光;偏光显微镜显示该样品主要由大量重晶石,混杂微量蓝铜矿、孔雀石及不透明金属矿物组成;X射线粉末衍射分析和红外光谱测试结果显示,该样品主要矿物以重晶石为主;拉曼光谱显示样品中蓝色部分为蓝铜矿,蓝绿色基底为重晶石,表面细小裂隙可见褐色透镜体为人造树脂充填物,揭示样品后期经过树脂充填处理。依据国家标准GB/T 16552-2017中的定名规则,建议定名为重晶石质玉(处理),在备注中注明局部含有蓝铜矿。

Recently the authors received 4 samples which were claimed to be“Qinghua jade”.The samples were tested by conventional gemmological tests and polarizing microscope,X-ray powder diffraction,Fourier transform infrared spectrometer,Raman spectrometer,SEM and EDS.The test results showed that the refractive index range of the sample measured by gem refractometer is 1.63-1.64(point measurement)and the relative density is about 4.17-4.20.Meanwhile,it showed weak fluorescence under long wave ultraviolet.Polarizing microscope test showed that the sample is mainly composed of a large number of barites,mixed with trace amounts of azurite,malachite and opaque metallic minerals.According to X-ray powder diffraction analysis,it showed that the main mineral component is barite.Raman spectrum showed,that the blue part of the sample is azurite,and the greenish blue basement is barite.There are small cracks on the surface of the sample where the synthetic resin brown lens body can be seen.This indicates that the sample has been filled with synthetic resin in the later stage.According to the GB/T 16552-2017,the sample is recommended to be named as barite jade(treated),and note that it contains azurite partially.