湖南汝城七彩(玉)石的组成与特征研究

An Analysis on Composition and Color Mechanism of Colored(JADE)Stones From Rucheng of Hunan Province

湖南汝城彩(玉)石是我省新发现的板岩类彩(玉)石矿产。目前,对该地区彩(玉)石组成与光谱学特征的研究较少,尤其是对其颜色成因的研究未见相关报道。研究采用宝石显微镜、偏光显微镜、波长色散型X射线荧光光谱、能量色散型X射线荧光光谱、X射线衍射、傅立叶变换红外光谱和紫外可见光光谱等分析技术对6件具有代表性的岩石样品进行化学成分、矿物组成及光谱学特征研究,并揭示其致色机理。岩矿鉴定显示样品主要为泥质、硅质或混合质板岩,富含石英、氧化铁质、黏土矿物和黄铁矿等矿物;X射线衍射分析表明样品主要由石英、云母、绿泥石、铁锰矿物、铁铜矿物、铁质矿物、锰质矿物、磁铁矿和菱铁矿等构成;X射线荧光光谱分析样品主要含有二氧化硅、氧化铁以及氧化铝等化合物,还含有Mn、Ti、Zn等其他金属元素;红外光谱显示在3438,1085,788,462 cm^(-1)处为石英特征峰,在1000,650,443 cm^(-1)处附近有绿泥石的特征谱峰,在波数为970 cm^(-1)处有云母的特征峰。通过能谱和紫外可见光谱综合分析6件样品都含有Fe元素,对其中8种不同的颜色原位分析测试表明:红棕色、黄色、浅黄色主要是含Fe元素,绿色含Cr元素,灰蓝色含Cu元素,而黑色主要含Fe和Mn元素。总之,湖南汝城板岩七彩(玉)石的颜色是由多种金属元素所形成的复杂矿物所致,结果对湘东南丁腰河组层位内七彩(玉)石找矿、成矿理论和应用研究提供参考。

Colored stone is a new type of ore variety emerging in the market in recent years.At present,there is a lack of research on the composition and spectral characteristics of color stone in this area.It,especially on the cause of its color,has not been reported.Based on the conventional valuable jade on the basis of analysis and test,we have made use of gem microscope,including the polarizing microscope,wavelength dispersive X-ray fluorescence spectroscopy,energy dispersive X-ray fluorescence spectroscopy,X-ray diffraction(XRD),fourier transform infrared spectrum in ultraviolet visible light spectrum analysis technology of 6 pieces of representative stone samples of characteristics of chemical composition and spectroscopy.It has tells us of the chromaticity mechanism.Rock ore identification shows that the samples are mainly argillaceous,siliceous or mixed slate.It is rich in quartz,ferric oxide,clay minerals and pyrite minerals.X-ray diffraction analysis shows that the samples are mainly composed of 76.4%~95.7%quartz,4.1%~21.3%mica and 0.2%~7.6%chlorite.The samples is analyzed by X-ray fluorescence spectrum in mainly contain compounds such as silicon dioxide,iron oxide and alumina,as well as other metal elements such as Mn,Ti and Zn.The spectra show that there are quartz characteristic peaks at 3438 cm^(-1),1085 cm^(-1),788 cm^(-1) and 462 cm^(-1),chlorite characteristic peaks at 1000 cm^(-1),650 cm^(-1) and 443 cm^(-1),and mica characteristic peaks at 970 cm^(-1).Six samples were analyzed by energy spectrum and UV-vis spectroscopy.The in-situ analysis of eight different colors show that the red brown,yellow and light yellow mainly with Fe.The green contains Cr,and the gray blue contains Cu and the black mainly contains Fe and Mn.All in all,the color origin of Rucheng slate colored jade is caused by complex minerals in a variety of metal elements.The results provide important reference for the exploration and metallogenic theory research of seven colored stone in dingyaohe Formation,southeast Hunan province.