俄罗斯“绿龙晶”的宝石学及谱学特征研究

Study on Gemological and Spectroscopic Characteristics of"Lvlongjing"from Russia

“绿龙晶”是产于俄罗斯的绿泥石玉,因其独特的颜色和花纹而受到人们的喜爱。目前有关“绿龙晶”的研究相对较少。本文通过常规宝石学仪器测试,红外吸收光谱、紫外―可见光吸收光谱、激光显微拉曼光谱以及X射线粉晶衍射等测试技术手段,对俄罗斯“绿龙晶”的宝石学特征、谱学特征及颜色成因进行了系统性研究。结果表明,俄罗斯“绿龙晶”颜色为深绿色至灰绿色,折射率约为1.57,相对密度为2.43~2.59,紫外长短波下呈荧光惰性,放大观察可见绿泥石晶体交叉排列,形成独特的花纹图案。红外吸收光谱测试表明,3660 cm^(-1)吸收峰为OH的伸缩振动所致,1045、1002、972 cm^(-1)三个吸收峰为Si-O对称伸缩振动所致,同时也是鉴定叶绿泥石的红外光谱特征峰;拉曼光谱测试表明,“绿龙晶”的拉曼特征峰出现在127 cm^(-1)、196 cm^(-1)、241 cm^(-1)、284 cm^(-1)、354 cm^(-1)、390 cm^(-1)、472 cm^(-1)、545 cm^(-1)、679 cm^(-1)、1059 cm^(-1)附近;粉末衍射谱线显示7.2008Å、4.7995Å、3.5967Å,为叶绿泥石的特征衍射峰;紫外―可见光吸收光谱存在以450 nm和495 nm为中心的宽吸收带,分别与Fe3+和Fe^(2+)的电子跃迁有关,推测“绿龙晶”的颜色与Fe元素相关;综合红外、拉曼和XRD测试分析可知,俄罗斯“绿龙晶”的主要组成矿物为叶绿泥石。

"Lvlongjing"is a chlorite jade from Russia,which is popular for its unique color and pattern.At present,there are relatively few studies on"Lvlongjing".In this paper,the gemological characteristics,spectroscopic characteristics and color genesis of the"Lvlongjing"from Russia were systematically studied by means of standard gemological testing,infrared spectroscopy,ultraviolet-visible spectroscopy,Raman spectroscopy and X-ray powder diffraction.The results show that the"Lvlongjing"from Russia is dark green to gray green color,refractive index of about 1.57,relative density of about 2.43~2.59,and the fluorescence is inert under long and short wavelength ultraviolet light.The cross arrangement of chlorite crystal aggregates can be observed by magnification,forming a unique pattern.The infrared absorption spectrum test shows that the absorption peak of 3660 cm^(-1)is caused by the stretching vibration of OH,and the three absorption peaks of 1045,1002 and 972 cm^(-1)are caused by the symmetrical stretching vibration of Si-O,which is also the characteristic peak of the infrared spectrum of penninite.Raman spectroscopy test showed that the Raman characteristic peaks of the“Lvlongjing”appeared near 127 cm^(-1),196 cm^(-1),241 cm^(-1),284 cm^(-1),354 cm^(-1),390 cm^(-1),472 cm^(-1),545 cm^(-1),679 cm^(-1),1059 cm^(-1).The powder diffraction lines are 7.2008Å、4.7995Å、3.5967Å,which are the characteristic diffraction peaks of penninite.The ultraviolet-visible spectroscopy has broad absorption bands centered at 450 nm and 495 nm,which are related to the electronic transitions of Fe3+and Fe^(2+),respectively.It is speculated that the“Lvlongjing”is related to Fe element in color.According to the analysis of infrared,Raman and XRD,the main mineral of the"Lvlongjing"is penninite.