Characteristics of Surrounding Rocks and Surface Residues of“Red Feldspar from Tibet”
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摘要: “西藏红色长石”的真伪及是否经过扩散处理是国内外珠宝界最激烈争议的话题之一, 对该长石材料的研究意义重要。采用传统的岩石学研究和现代岩矿测试相结合的方法, 运用偏光显微镜, 电子探针, X射线光能谱仪等测试手段对“西藏红色长石”的围岩和表面残留物的宝石学特征进行了研究。结果表明, “西藏红色长石”原生围岩是中基性侵入岩, 围岩中含有玻璃和气孔, 围岩和长石表面的残留物中含有大量的Cu, Fe元素; 围岩和残留物经过了后期人为的高温烧结作用, 部分暗色矿物和外来物质在烧结过程形成为玻璃, 并产生大量的气泡; 绝大部分“西藏红色长石”样品都经过了Cu扩散处理。Abstract: Since 2008, whether the“red feldspar from Tibet”exists and whether such a stone is diffusedly-treated have been hot-debated issues in the gemmology communities at home and abroad.The gemmological characteristics of the surrounding rocks and the surface residues of the“red feldspar from Tibet”are studied presently by using the polarizing microscope, electron microprobe and X-ray photoelectron spectroscopy techniques.The results show that the original host rocks of the“red feldspar from Tibet”are composed mainly of intermediate-basic intrusive rocks containing glasses and bubbles, and that the surface residues of the red feldspar and its surrounding rocks contain plenty of copper and iron.Furthermore, the surrounding rocks and surface residues may have artificially been sintered at a high temperature in their later development stage.In this sintering process, part of dark minerals and some foreign substances such as co-solvents turned into glasses and bubbles.Further tests reveal that the majority of the“red feldspar from Tibet”samples under investigation might have been copper-diffusedly-treated.
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