粉色—紫色缅甸尖晶石热处理前后紫外-可见光谱分析

任芊芊; 陈美华; 王成思; 吴改

粉色—紫色缅甸尖晶石热处理前后紫外-可见光谱分析

1. 中国地质大学珠宝学院, 湖北武汉 430074;
2. 中国地质大学地球科学学院, 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GICTXM-201502

详细信息

作者简介:
任芊芊(1989-),女,硕士研究生,主要从事宝石学方面的研究。

中图分类号: TS93
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出版历程
- 收稿日期: 2016-01-24
- 刊出日期: 2021-09-08

Analysis of UV-Vis Spectrum on Pink-Purple Spinel from Burma before and after Heat Treatment

1. Gemmological Institute, China University of Geosciences, Wuhan 430074, China;
2. School of Earth Sciences, China University of Geosciences, Wuhan 430074, China

摘要

摘要: 选取5颗粉色—紫色缅甸尖晶石原石为实验样品，分别在1 200℃和1 600℃下进行恒温10 h的热处理实验。通过分析样品成分及热处理前后紫外-可见光谱，发现粉色—紫色尖晶石样品均为含微量Fe元素的镁铝尖晶石，且在350~600 nm范围内出现吸收带的位置基本相同，其致色原因与八面体中Fe³⁺和四面体中Fe²⁺的自旋禁阻跃迁及二者间电荷耦合作用有关。对比样品的两次热处理后紫外-可见光谱结果发现，热处理过程促进350~430 nm及500~600 nm范围内吸收强度增加，前者与高温下尖晶石内部结构无序引起近紫外区O^2-→Fe²⁺、Fe³⁺离子间电荷转移作用增加有关，后者由进入四面体内部Fe³⁺同相邻位置内Fe²⁺共同作用产生。在经1 600℃热处理后，近紫外区吸收边强度再次增加使样品光谱发生明显改变，色调偏红，部分样品因热处理诱发内部裂隙、透明度降低，热处理效果不明显。
- 尖晶石 /
- 热处理 /
- 紫外-可见光谱 /
- 缅甸
Abstract: In this paper, 5 pieces of pink-purple spinels from Burma were selected as experimental samples and heated at 1 200℃ and 1 600℃ for 10 hours respectively.Through laser induced breakdown spectroscopy (LIBS) analysis for the chemical compositions and UV-Vis spectroscopy, it was found that all samples were MgAl₂O₄ with trace amount of element Fe and the UV-Vis absorption bands were basically the same in the range 350-600 nm.The causes for their colours may be related to spin-forbidden transition of Fe³⁺ in octahedral site and Fe²⁺ in tetrahedral site and charge transfer between these pairs.Comparing UV-Vis spectra before and after heat treatment, it was found that the absorption intensity of all samples were enhaced dramatically in 350-430 nm and 500-600 nm areas.The absorption band at 350-430 nm is believed to be caused by increasing intervalence charge transfer between O^2-→Fe²⁺、Fe³⁺ after the disorder structural transition.The absorption band at 500-600 nm is believed to be caused by Fe³⁺ in tetrahedral site effected by Fe²⁺ in adjacent site.After the heat treatment at temperature of 1 600℃, the absorption intensity in near ultraviolet region increased again and led to a clear change in UV-Vis spectrum, which making the apparent colour of samples become redder, however, some samples fail to follow this result due to internal fissures and lower transparency.
- spinel /
- heat treatment /
- UV-Vis /
- Burma

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参考文献(26)

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粉色—紫色缅甸尖晶石热处理前后紫外-可见光谱分析

作者简介: 任芊芊(1989-),女,硕士研究生,主要从事宝石学方面的研究。

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出版历程

Analysis of UV-Vis Spectrum on Pink-Purple Spinel from Burma before and after Heat Treatment

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目录

作者简介:
任芊芊(1989-),女,硕士研究生,主要从事宝石学方面的研究。