Study on the Gemological Characteristics of an Illite-imitated Dushan Jade
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摘要:
为了确定一种仿独山玉样品的真伪,采用薄片鉴定、X射线粉末衍射法和电子探针分析对样品进行了分析测试。测试结果表明,该样品由伊利石和少量的绢云母组成,并不含有斜长石、铬云母等组成独山玉的矿物相,是一种独山玉的仿冒品。此外,结合显微鉴定特征和电子探针分析结果,笔者初步推断该样品所呈现的翠绿色为铁元素致色。这种仿冒品在外观上与独山玉很相似,常规宝石学参数也相似,但前者的硬度低于独山玉的。由于硬度检测属于有损检测,因此,建议检测机构在日常检测工作中结合红外光谱仪进行检测。
Abstract:In order to determine the authenticity of a Dushan jade sample, it was analyzed by thin section identification, XRD powder diffraction and electron probe analysis. The test results showed that the sample was composed of illite and a small amount of sericite without plagioclase, mica and any other mineral phases that constitute Dushan Jade, implying that it was a counterfeit product. In addition, combined with the microscopic identification characteristics and electron probe analysis results, the author preliminarily concluded that the emerald green color present in the sample was due to the coloration of iron element. This counterfeit product is similar in appearance to Dushan Jade, and the conventional gemological parameters are also similar. But the hardness of the former is lower than that of Dushan Jade. Since the hardness test is a lossy test, it is recommended that the testing organization apply the infrared spectrometer for daily inspection.
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Key words:
- imitated Dushan Jade /
- illite /
- X-ray diffraction /
- infrared spectrum /
- electronic probe
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表 1 翠绿色仿独山玉样品的化学成分 /%
Table 1. Electron probing analysis of the emerald imitated Dushan jades
检测点 Na2O MgO Al2O3 SiO2 K2O CaO TiO2 Cr2O3 MnO Fe2O3 总量 1 0.446 0.213 26.980 48.075 10.014 0.332 0.210 0.076 0 1.244 87.590 2 1.276 0.208 26.230 48.513 10.370 0.518 0.352 0.025 0.017 1.323 88.833 3 0.429 0.223 27.087 47.684 10.051 0.378 0.155 0.035 0 1.500 87.541 4 0.679 0.230 27.258 48.357 10.014 0.524 0.126 0.053 0.039 1.434 88.713 5 1.361 0.193 32.428 49.273 11.126 0.202 0.075 0.059 0.050 1.054 95.821 6 1.435 0.189 31.995 47.414 11.735 0.315 0.107 0.032 0 1.161 94.381 Average 0.938 0.209 28.663 48.219 10.552 0.378 0.171 0.047 0.018 1.286 90.480 测试单位:中国地质科学院郑州矿产综合利用研究所;仪器型号:日本岛津EPMA-1720。 -
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