天河石的颜色成因探讨

Discussion of Colour Origin in Amazonite

在充分查阅了大量前人的资料的基础上,对5个天河石样品进行常规宝石学测试,并借助大型仪器对其进行深入的研究。激光剥蚀电感耦合等离子体技术测试发现,天河石的微量元素Fe、Rb和Pb的质量分数较多;显微红外光谱对结构水测试发现,在3 800~3 200cm^(-1)范围内显示有结构水和液态水的吸收;显微紫外-可见吸收光谱测试显示以380、625、740nm为中心的强吸收。观察讨论天河石对可见光的吸收,结合热处理和辐照处理的结果,综合比较前人的研究结果,得出影响天河石颜色的三个吸收区域(625nm中心、740nm中心和380nm中心)都是空穴缺陷造成的,与结构水并无直接的关系。

Based on the literatures,we studied gemmological characteristics of five amazonite samples,and conducted in-depth research with the help of advanced instrumentation.The contents of trace elements(Fe,Rb and Pb)were obtained by laser ablation inductively coupled plasma mass specrtrometry(LA-ICP-MS).We identified structural water and liquid water among 3 800~3 200 cm-1 using microscopic FTIR spectroscopy.We found three strong absorption centers at 380、625 nm and 740 nm by using microscopic UV-Vis spectrophotometer.Comparing the results from heat treatment and irradiation treatment,we concluded that the hole-related centers at 380,640 nm and 725 nm caused its colour.The colour has no direct relation with the structural water.