“台山玉”的矿物组成

Mineral Component of Jade from Taishan

"台山玉"产自广东省台山市,是一种石英质玉石。笔者挑选了19件典型的"台山玉"样品,通过偏光显微镜、红外光谱仪、X射线粉末衍射仪、X射线荧光光谱仪对其成分及结构进行测试分析。结果发现,"台山玉"的主要矿物组成是石英和高岭石,并含有少量的绢云母、粉尘状铁质、绿帘石等;"台山玉"的主要矿物石英的结晶度高于玉髓的结晶度;黄色和红色系列"台山玉"样品中都含有粉末状铁质。"台山玉"的X射线荧光光谱结果显示,其褐黄色-褐红色部位中Fe的质量分数较高,颜色越深,X射线荧光光谱的强度越强。黄色及红色系列的"台山玉"的颜色成因是Fe致色。

Jade from Taishan is a fine grained quartzite, which is mined from Taishan, Guangdong Province. In this paper, the components and structures of 19 typical jades from Taishan were tested and analyzed by polarizing microscope, infrared spectroscope, X ray powder diffraction, and X-ray fluorescence spectrometer. The results show that the main components of jade from Taishan are quartz and kaolinite, with a small amount of sericite, dust-like iron minerals, epidote and other minerals. The crystallinity of quartz in jade from Taishan is better crystallized than that of chalcedony. The yellow and red series of jade from Taishan contain fine grained iron minerals. X-ray fluorescence spectra show that content of Fe is higher in the brown yellow-maroon areas of jade from Taishan, and the intensity of X- ray fluorescence is proportional to the intensity of the colour. Therefore, Fe is believed to he the main colour causing agent in jade from Taishan.