The Spectral Characterization of Blue Spinel and Other Blue Gemstones with the Alexandrite Effect  

作　　者：Jiling Zhou Chengsi Wang Xishan Zhao Yunqi Yang Andy Hsitien Shen 

机构地区：[1]Gemmological Institute,China University of Geosciences,Wuhan 430074,China [2]Hubei Gems and Jewelry Engineering Technology Research Center,Wuhan 430074,China [3]Shenzhen Research Institute of China University of Geosciences,Shenzhen 518000,China [4]Guangzhou CUG Gems and Jewelry Testing Co.,Ltd.,Guangzhou 510000,China

出　　处：《宝石和宝石学杂志（中英文）》2024年第4期69-76,共8页Journal of Gems & Gemmology

基　　金：This research was funded by the Youth Foundation Project,Basic and Applied Research Foundation of Guangdong Province of China(2022A1515110780);China Postdoctoral Science Foundation(2023M743293);China Univerisity of Geosciences(Wuhan)Gemmological Institute research project(GICTXM-04-S202103).

摘　　要：In gemmology,the term“Alexandrite effect”is used to describe colour change phenomenon when a gemstone is observed under different light sources,usually between daylight and incandescent light.The definition of the Alexandrite effect is constantly being broadened with new discovery of gem resource.The traditional definition of the Alexandrite effect attributing the colour change phenomenon to the presence of two maximum transmission regions and a maximum absorption region in the absorption spectra.In this study,7 blue spinels and 5 blue gemstones(including tanzanite,kyanite,fluorite,and 2 sapphires)showing the Alexandrite effect were investigated.The goal is to explain the cause of blue-to-violet Alexandrite effect and the spectral features causing such colour change.In the UV-Vis spectra,all samples showed a maximum absorption peak in the range of 534-610 nm,within the green region to orange region.The traditional explanation of green to red Alexandrite effect required a transmission window in the red region;however,some of our samples did not show this transmission window and the blue-to-violet Alexandrite effect was still visible.Therefore,it is incomplete to explain the mechanism of the Alexandrite effect according to their characteristic absorption spectra,a systematic study based on modern colour science and colour perception in human vision is required to elucidate the blue-to-violet Alexandrite effect.

关 键 词：blue spinel Alexandrite effect absorption spectrum 

分 类 号：TS93[轻工技术与工程]