Raman Spectra Study of Thermal Transformation of Nephrite Cat’s Eye from Sichuan Province
LU Bao-qi1, XIA Yi-ben1, QI Li-jian2, YOU Jing-lin1
1. School of Materials and Engineering, Shanghai University, Shanghai 200072，China 2. Gemology Institute, China University of Geosciences, Wuhan 430074，China
Abstract：Raman spectrum and X-ray powder diffraction (XRD) were used to study the process and product of thermal transformation of nephrite cat’s eye from Sichuan province. The results indicate that upon being heated till 900 ℃, tremolite in the nephrite cat’s eye is dehydrated completely and the appearance of a new characteristic band near 671 cm-1 indicates the form of a new product. At 1 000 ℃, the intensity of band near 1 014 cm-1 rises obviously, and the weak bands near 573 cm-1and 934 cm-1 present. Up to 1 100 ℃, the band near 1 033 cm-1appears. All these evidences show that the final thermal transformation product is identified as Ca—Mg pyroxene which is similar to diopside both in structure and in composition. This conclusion is confirmed by XRD.
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