缅甸紫色翡翠的致色机理——光谱和色度学研究  

Colouration in purple jadeite-jade from Myanmar: A spectroscopy and chromaticity investigation

作　　者：商嫣然 王伟钊 金天力 黄琳铭 吴中允 郭颖[1] SHANG Yan-ran;WANG Wei-zhao;JIN Tian-li;HUANG Lin-ming;WU Zhong-yun;GUO Ying(School of Gemmology,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)珠宝学院,北京100083

出　　处：《岩石矿物学杂志》2024年第3期643-651,共9页Acta Petrologica et Mineralogica

摘　　要：采用电子探针分析、能量色散X射线荧光光谱、傅里叶变换红外光谱、紫外-可见光谱和色度学方法等多种手段,对55个缅甸紫色翡翠样品进行了全面分析。结果表明,缅甸紫色翡翠的主要化学成分为SiO_(2)、Al_(2)O_(3)和Na_(2)O,含量与标准硬玉接近。色度学测试分析显示,缅甸紫色翡翠的彩度C^(*)主要受色度值a^(*)控制,而色调角h°主要由色度值b^(*)控制。缅甸紫色翡翠可分为两种类型:Ⅰ型紫色翡翠主要由Mn^(3+)致色,并在紫外-可见-近红外光谱570 nm显示主要吸收带;Ⅱ型紫色翡翠由于Fe^(2+)-Ti^(4+)之间的电荷转移致色,在光谱540 nm和610 nm显示吸收。两种翡翠中均存在Fe^(3+)的吸收峰,样品中的全铁含量决定其色调角及明度。55 Myanmar purple jadeite-jades samples were comprehensively analyzed by electron microprobe analysis(EMPA), energy-dispersive X-ray fluorescence(ED-XRF) spectroscopy, Fourier transform infrared(FTIR) spectroscopy, ultraviolet-visible(UV-VIS) spectroscopy and colorimetric methods. The results show that the main chemical compositions of Myanmar purple jadeite-jades are SiO_(2), Al_(2)O_(3) and Na_(2)O, and the contents are close to those of standard jadeite. Chromaticity test analysis showed that the chroma C^(*) of purple jadeite-jade is mainly controlled by the colour coordinate a^(*), while the hue h° is mainly controlled by the colour coordinate b^(*). Myanmar purple jadeite-jades can be classified into two types: Type Ⅰ show the main absorption bands at 570 nm which is assigned by chromophore Mn^(3+) and Type Ⅱ with two main absorptions at 540 nm and 610 nm are colored by charge transfer between Fe^(2+)-Ti^(4+). The absorption peaks of Fe^(3+) existed in both types of Myanmar purple jadeite-jades, and the full iron content in the samples determined their hue and lightness.

关 键 词：缅甸紫色翡翠 颜色成因 光谱学 宝石色度学 

分 类 号：P578.954[天文地球—矿物学] P579[天文地球—地质学]