Black nephrite is a very uncommon jade type currently found only at Karakashi. In order to study the spectral characteristics and color-genetic mechanism of the black nephrite, samples collected from Karakashi were studied using EMPA, IR, Raman and XRD. The results are as follows: nephrite with different color has nearly the same major chemical compostions, while the black ones contain higher carbon; nephrite with different color has similar vibration spectrum, while the black ones show characteristic peak of graphite. It is speculated that the color of black nephrite is not only related with actinolite, but also related with the graphite inclusions. Obviously, Raman spectra is a very important nondestructive method to identify the color genesis and the origin of the black nephrite.%采用X射线荧光光谱仪、X射线粉晶衍射仪、红外光谱仪、拉曼光谱仪等对黑色透闪石质软玉样品进行化学成分和谱学特征研究.通过X射线粉晶衍射判定所采样品全部属于透闪石质软玉,采用红外光谱仪和拉曼光谱仪对样品进行振动光谱测试,并结合化学成分测试结果分析墨玉的组成和颜色成因.结果显示,黑色透闪石质软玉可分为两种:由含铁量较高的阳起石组成的(TFe2 C3:7.47Wt％～11.97 Wt％),另外一种是由透闪石和石墨组成,并且含铁量比较低(TFe2O3:0.56 Wt％～4.74 Wt％).两者的振动光谱特征与透闪类矿物基本一致,在含石墨透闪石的拉曼光谱中出现了石墨特征峰1581 cm-1.因此,拉曼光谱在区分阳起石致色和石墨致色的黑色透闪石质软玉比红外光谱更加敏锐,该方法可以成为无损鉴定黑色透闪石质软玉颜色成因和产地来源的重要辅助手段.
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