Gemmological and Mineralogical Characteristics of Dingqing Ivory-jade in Tibet
-
摘要:
矿床产于西藏丁青县,其质地温润细腻,色如象牙,故得名“象牙玉”, 矿石呈砾石状,部分呈磨圆状、椭圆状。运用紫外可见光谱、X射线荧光光谱、红外光谱、X射线粉晶衍射及扫描电镜等技术对象牙玉进行了玉石学及矿物学特征研究。结果表明:象牙玉摩氏硬度在4~6,相对密度2.92~3.05,折射率1.62~1.70,无多色性,无特征吸收谱带,主要矿物成分为菱镁矿(MgCO3),少量石英(SiO2),微量方解石(CaCO3)。丁青象牙玉的玉石学及矿物学特征可作为产地鉴定的依据。
Abstract:This deposit is located in Dingqing county, Tibet. Its texture is warm and delicate, and its color is like ivory, so it is named "Ivory jade". The ore is gravel-shaped, and some of it is round and oval. The gemmological and mineralogical characteristics of Dingqing Ivory-jade from Tibet are studied by means of UV-Vis Spectroscopy, X-ray Fluorescence Spectroscopy, Infrared Spectroscopy, XRD and SEM. The results show that: the Mohs hardness of Ivory-jade is 4~6, the relative density is 2.92~3.05, the refractive index is 1.62~1.70, no polychromism nor characteristic absorption band, the main mineral composition is magnesite (MgCO3), with a small amount of quartz (SiO2), trace calcite (CaCO3). The gemmological and mineralogical characteristics of Dingqing Ivory-jade can be used as the basis of its origin identification.
-
Key words:
- UV-Vis spectroscopy /
- X-ray fluorescence spectroscopy /
- Infrared spectroscopy /
- XRD /
- SEM /
- Ivory-jade
-
-
表 1 丁青象牙玉的玉石学特征
Table 1. Gemmological characteristics of Dingqing Ivory-jade
样品编号 摩氏硬度 密度 折射率 相对密度(内部) 相对密度(整体) DQXY-1 5~6 2.98 3.05 1.63~1.68 DQXY-2 5~6 2.96 2.95 1.63~1.68 DQXY-3 4~5 2.95 2.96 1.62~1.69 DQXY-4 5~6 2.97 2.93 1.63~1.68 DQXY-5 5~6 2.96 3.02 1.62~1.69 DQXY-6 5~6 2.92 2.92 1.62~1.68 DQXY-8 5~6 2.94 2.94 1.63~1.68 DQXY-9 5~6 2.92 2.92 1.62~1.70 表 2 X射线荧光光谱半定量分析结果/%
Table 2. Results of semi-quantitative analysia by X-ray fluorescence spectroscopy
样品编号 CO2 MgO Al2O3 SiO2 P2O5 SO3 K2O CaO TiO2 DQXY-1 55.53 37.31 0.201 5.40 0.0071 0.0795 0.0444 0.88 0.0053 DQXY-5 57.92 40.87 0.0890 1.16 0.0034 0.0201 0.0175 0.291 0.0030 样品编号 MnO Fe2O3 ZnO SrO BaO Er2O3 NiO Co3O4 DQXY-1 0.114 0.582 0.0017 0.0018 0.0215 0.0016 0.26 0.012 DQXY-5 0.0995 0.378 0.0105 0.196 0.0052 表 3 X-射线粉晶衍射分析
Table 3. X-ray powder diffraction analysis
样品编号 矿物含量/% 总含量/% 石英 方解石 菱镁矿 DQXY-1 5.15 1.05 93.80 100.00 DQXY-2 0.80 0.83 98.37 100.00 DQXY-3 5.80 0.35 93.85 100.00 DQXY-4 0.71 0.41 98.88 100.00 DQXY-5 1.13 0.34 98.53 100.00 DQXY-6 5.05 94.95 100.00 DQXY-8 0.75 99.25 100.00 DQXY-9 0.44 99.56 100.00 表 4 样品能谱分析结果
Table 4. Results of sample energy spectrum analysis
样品编号 C Mg Si O 重量/% 原子/% 化合物/% 化学式 重量/% 原子/% 化合物/% 化学式 重量/% 原子/% 化合物/% 化学式 重量/% 原子/% DQXY-1 15.64 21.61 57.30 CO2 24.15 16.49 40.04 MgO 1.24 0.74 2.66 SiO2 58.97 61.17 DQXY-4 14.84 20.69 54.36 CO2 27.52 18.96 45.64 MgO 57.64 60.35 DQXY-5 10.48 15.33 38.41 CO2 1.00 0.73 1.67 MgO 28.01 17.52 59.92 SiO2 60.50 66.42 -
[1] 韩 冬, 刘喜锋, 刘 琰, 等. 新疆和田地区大理岩型和田玉的形成及致色因素探讨[J]. 岩石矿物学杂志, 2018, 37(6):1011-1026. doi: 10.3969/j.issn.1000-6524.2018.06.013
HAN D, LIU X F, LIU Y, et al. Genesis of dolomite-related nephrite from Hetian and color-forming factors of typical nephrite in Hetian, Xinjiang[J]. Acta Petrologica et Mineralogica, 2018, 37(6):1011-1026. doi: 10.3969/j.issn.1000-6524.2018.06.013
[2] 高静, 巫翔, 秦善. X射线吸收谱在宝石学研究中的应用[J]. 岩石矿物学杂志, 2014, 33(S2):155-160.
GAO J, WU X, QIN S. The application of X-ray absorption spectroscopy to gemology[J]. Acta Petrologica et Mineralogica, 2014, 33(S2):155-160.
[3] 郭立鹤, 韩景仪. 和田玉、玛纳斯碧玉和岫岩老玉中M1、M3阳离子占位的红外光谱分析[J]. 岩石矿物学杂志, 2002, 21(S1):68-71. doi: 10.3969/j.issn.1000-6524.2002.z1.012
GUO L H, HAN J Y. The IR analyses of M1 and M3 cation occupation of Hetian jade, Manasi green jade and Xiuyan old jade[J]. Acta Petrologica et Mineralogica, 2002, 21(S1):68-71. doi: 10.3969/j.issn.1000-6524.2002.z1.012
[4] 刘飞, 余晓艳. 中国软玉矿床类型及其矿物学特征[J]. 矿产与地质, 2009, 23(4):375-380. doi: 10.3969/j.issn.1001-5663.2009.04.017
LIU F, YU X Y. Classification and mineralogical characteristics of nephrite deposits in China[J]. Mineral Resources and Geology, 2009, 23(4):375-380. doi: 10.3969/j.issn.1001-5663.2009.04.017
[5] 潘兆橹. 结晶学及矿物学(上册)[M]. 北京: 地质出版社, 1993.
PAN Z L. Crystallography and Mineralogy(the first volume)[M]. Beijing: Geological Publishing House, 1993.
[6] 汤惠民. 行家这样买宝石[M]. 南昌: 江西科学技术出版社, 2011: 233-240.
TANG H M. Connoisseur buy gemstones like this[M]. Jiangxi Science and Technology Press, 2011, 233-240.
[7] 许雅婷, 陈涛. 老挝北部黄色图章石的矿物成分及微量元素特征[J]. 岩石矿物学杂志, 2019, 38(3):399-409. doi: 10.3969/j.issn.1000-6524.2019.03.009
XU Y T, CHENG T. Mineral composition and trace element characteristics of Laos Northern Yellow Stone[J]. Acta Petrologica et Mineralogica, 2019, 38(3):399-409. doi: 10.3969/j.issn.1000-6524.2019.03.009
-