赞比亚墨绿色电气石的颜色成因初探

仲佩佩; 沈锡田

doi:10.15964/j.cnki.027jgg.2017.06.002

赞比亚墨绿色电气石的颜色成因初探

仲佩佩,
沈锡田^,

中国地质大学珠宝学院, 湖北武汉 430074

基金项目:

中国地质大学(武汉)珠宝检测技术创新中心开放基金(CIGTXM-S201513)，

详细信息

作者简介:
仲佩佩(1992-),女,硕士研究生,主要从事宝石学研究工作。

通讯作者:
沈锡田(1962-),男,教授,主要从事宝石学与矿物学研究工作。E-mail:ahshen@foxmail.com

中图分类号: TS93
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出版历程
- 收稿日期: 2017-05-23

Colour Origin of Dark Green Tourmaline from Zambia

Gemmological Institute, China University of Geosciences, Wuhan 430074, China

摘要

摘要: 目前,对于绿色电气石的颜色成因仍存在争议。对赞比亚墨绿色电气石的不同方向和不同颜色区域进行LA-ICP-MS、电子探针以及偏振显微紫外-可见光谱测试,结果显示其化学成分以Al₂O₃和SiO₂为主,还含有一定量的FeO_T、MnO等杂质,其中Fe和Mn元素的质量分数较高;不同方向以及不同色带区域的微量元素的质量分数测试结果显示,赞比亚墨绿色电气石的墨绿色由Fe和Mn元素造成。偏光显微紫外-可见吸收光谱对不同色区及不同方向测试结果显示,都存在415,720 nm处吸收带,其中415 nm处吸收带主要与交换耦合Fe³⁺—Fe³⁺离子对的电荷转移、Mn²⁺的d电子跃迁吸收有关,720 nm处吸收带主要与Fe²⁺—Fe³⁺离子对间的电荷转移跃迁有关。结果初步认为,赞比亚墨绿色电气石的主要致色成因是Fe和Mn元素致色。
- 电气石 /
- 颜色成因 /
- 电子探针 /
- 紫外-可见吸收光谱 /
- 赞比亚
Abstract: A series of tests have been conducted on dark green tourmaline crystals from Zambia, including conventional characteristics, LA-ICP-MS, EPMA and microscopic polarized UV-Vis absorption spectra in order to fully understand their colour origin. Electron micro-probe results indicated that, mass fraction of Al₂O₃ and SiO₂ are high in the tourmaline samples, and a certain amount of FeO_T,MnO,TiO₂ and Cr₂O₃ are contained, while FeO_T is relatively higher. EPMA results showed the content of the trace element of different directions and colour zones. Dark green area contains more content of Fe. Microscopic polarized UV-Vis absorption spectra showed that all samples have strong absorption bands centered at 415 nm and 720 nm. The absorption band near 415 nm is assigned to charge transfer between Fe³⁺-Fe³⁺, as well as Mn²⁺. The absorption band near 720 nm is usually ascribed to the charge transfer between Fe²⁺-Fe³⁺. The intricate interplay between these two bands is the main cause of the colour that we observed.
- tourmaline /
- colour origin /
- EPMA /
- UV-Vis spectrum /
- Zambia

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参考文献(11)

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