中国岫岩玉的致色机理及色度学研究

通过岫岩玉的成分、过渡金属离子的价态及配位状态来研究岫岩玉的致色机理。电感耦合等离子原子发射光谱(ICP-AES)结果显示样品中除了铁和锰，几乎没有其他过渡金属元素。电子顺磁共振谱(EPR)则揭示了位于八面体晶格上的Mn2+和位于四面体和八面体晶格上的Fe3+，而吸收光谱(OAS)则证实了Fe2+和Fe3+的共同存在。分析结果表明Fe2+对岫玉的绿色起主要作用而岫玉的黄色则是由Fe2+和Fe3+的共同作用决定的。此外通过漫反射光谱(DRS)计算出岫玉的色度坐标，对比发现人眼感觉颜色类似的样品其实色度坐标有很大差异。因此可以通过色度坐标来定量区分岫玉颜色的差异，这具有一定的学术价值和经济价值。

Coloration Mechanism and Chromaticity of Xiuyan Jade of China

The coloration mechanism of Xiuyan Jade was studied with the chemical composition,valance and coordination states of transition metal ions.The result of inductively-coupled plasma atom emission spectrometer(ICP-AES) indicated that there are little other transition metal elements except for iron and manganese.Electron paramagnetic resonance(EPR) revealed that Fe3+ ions locate at both octahedral sites and tetrahedral sites.Optical absorption spectrum(OAS) showed the presence of Fe2+ and Fe3+ ions.Moreover,depending on the results of OAS,Fe2+ ions determine the green color of Xiuyan Jade,while the coexistence of Fe3+ and Fe2+ ions introduces the yellow color of Xiuyan Jade.The chromaticity coordinate was calculated according to diffuse reflectance spectrum.The result demonstrated that chromaticity coordinates can be used to quantitatively distinguish Xiuyan Jade with similar color,which can provide a scientific reference for the evaluation of the value of Xiuyan Jade.