云南宝石级锡石的光谱特征研究

Study on spectral characteristics of gem grade cassiterite in Yunnan

锡石作为稀有宝石之一,具有良好的宝石学特性及出色的火彩。因锡石出色的火彩和超强的光泽,一度被称为“云南钻石”,因为在全世界范围内能作为宝石级锡石的产出相对较少,加之地质因素和开采技术的限制,国内对锡石的研究主要偏重于地质特征、锡石浮选的研究,而对锡石宝石学特征的研究相对较少,尤其是对达到宝石级的锡石在有关宝石学方面的研究更是少之又少。通过对5颗产于云南的黄—棕褐色宝石级刻面锡石进行了常规宝石学测试和谱学测试,从而对云南锡石进行宝石学性质及谱学特征分析,并对其颜色成因进行初步探讨。初步分析云南西盟宝石级锡石的颜色成因与其他地区锡石颜色成因不同,其颜色在一定程度上不仅可能受Si、Ca元素影响,也与可能与大量包裹体有关。

Cassiterite,as a rare gem,has good gemological characteristics and excellent fire color.Cassiterite is called“Yunnan diamond”because of its excellent fire color and super luster.Because the production of cassiterite as gem grade is relatively small in the world,coupled with the limitation of mining technology and geological factor,the domestic research on cassiterite mainly focuses on the geological characteristics,cassiterite flotation,but the study about gemological characteristics of cassiterite are relatively fewer.Especially,there are very few gemological studies on cassiterite that has reached gem quality.Five yellow brown gem grade faceted cassiterite produced in Yunnan are tested by conventional gemology and spectral test.Therefore,the gemological properties and spectral characteristics of Yunnan cassiterite are analyzed,and the cause of its color is preliminarily discussed.Preliminary analysis result shows that the color origin of precious cassiterite in Ximeng,Yunnan is different from that of cassiterite in other areas.To some extent,its color might be influenced not only by Si and Ca elements,but also by a lot of inclusions.