Abstract：Raman spectra, infrared spectra, chemical composition analysis, and UV-Vis NIR spectra analysis were carried out for new turquoise imitations in gem wholesale markets. The main spectral characteristics were summarized. The results show that the imitations are mainly composed of a single component or multiple mixed components of barite, gibbsite, and calcite powder, which are pressed, cemented by epoxy resin or acrylate, and dyed. The infrared spectra results are as follows: The imitations of a single mineral component are significantly different from turquoise. The imitation of barite shows a 1 078 cm-1 absorption peak caused by [SO4]2- asymmetric stretching vibration and the imitation of calcite shows a 1 476± cm-1 absorption peak caused by [CO3]2- symmetric stretching vibration. The multi-component imitations can be seen to integrate the absorption spectra of various mineral characteristics, the spectral characteristics are complex. According to the missing water peak, or only showing the absorption peaks of 3 623, 3 528, 3 472, and 3 388 cm-1 caused by the stretching vibration of OH- of gibbsite, and there are [SO4]2- and [CO3]2- groups correlated absorption peaks in the fingerprint region, we can roughly distinguish the imitations from turquoises. The micro-Raman spectra show that the mineral compositions of the multi-component imitations are different at different test locations, and the characteristic peaks of gibbsite (3 360，3 432，3 522，3 614 cm-1), barite (989 cm-1） and calcite (1 088 cm-1） can be measured respectively. Combined with the results of micro-Raman spectra and chemical analysis, the specific mineral composition of the imitation product can be further confirmed. The UV-Vis-NIR spectra show that the samples are dyed and showed 633± nm, 713± nm or 610± nm, and 675± nm broad absorption peaks.
杨池玉，汪田田，张维肖，汤维茜. 单一及多组分混合物绿松石仿制品的光谱学特征研究[J]. 光谱学与光谱分析, 2025, 45(01): 183-190.
YANG Chi-yu, WANG Tian-tian, ZHANG Wei-xiao, TANG Wei-xi. Study on Spectral Characteristics of Turquoise Imitations of Single and Multiple Component Mixtures. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(01): 183-190.
[1] ZHU Lin, HE Chong, YANG Ming-xing, et al(祝 琳，何 翀，杨明星，等). Journal of Gems & Gemmology(宝石和宝石学杂志)，2017，19(6): 15.
[2] QU Yan(曲 雁). Journal of Gems & Gemmology(宝石和宝石学杂志)，2017，19(4): 25.
[3] YAN Jun, LIU Xiao-bo, WANG Ju-an, et al(严 俊，刘晓波，王巨安，等). Rock and Mineral Analysis(岩矿测试)，2015，34(5): 544.
[4] ZHANG Yu-chen, XU Wen-ying, ZHAO Bo-wen, et al(张瑜晨，徐文颖，招博文，等). Journal of Gems & Gemmology(宝石和宝石学杂志(中英文))，2021，23(1): 40.
[5] Feairheller Jr W R, Katon J E. Spectrochimica Acta Part A: Molecular Spectroscopy，1967，23(8): 2225.
[6] Chike K E, Myrick M L, Angel S M, et al. Applied Spectroscopy，1993，47(10)：1631.
[7] Hana Vaskova，Vojtěch K( rˇ )esálek. Raman Spectroscopy of Epoxy Resin Crosslinking. Proceedings of The 13th WSEAS International Conference on Automatic Control, Modelling &Simulation, 2011: 357.
[8] ZHU Ying, LI Yan-zhang, LU An-huai, et al(朱 莹，黎晏彰，鲁安怀，等). Earth Science Frontiers(地学前缘)，2022，29(1): 459.
[9] Marco De La Pierre, Cédric Carteret, Lorenzo Maschio, et al. The Journal of Chemical Physics, 2014, 140(16): 164509.
[10] Ruan H, Frost R, Kloprogge J. Journal of Raman Spectroscopy, 2001, 32: 745.
[11] GB/T 36168—2018 Turquoise Testing(绿松石鉴定)[S], 2018.
[12] WEN Lu, LIANG Wan-xue, ZHANG Zheng-gang, et al(闻 辂，梁婉雪，章正刚，等). Infrared Spectroscopy of Minerals(矿物红外光谱学). Chongqing：Chongqing University Press(重庆: 重庆大学出版社)，1989. 65.
[13] XU Pei-cang, LI Ru-bi(徐培苍，李如壁). Raman Spectroscopy in Geoscience(地学中的拉曼光谱). Xi'an: Shaanxi Science and Technology Press(西安：陕西科学技术出版社)，1987.
[14] XU Feng-shun, CHEN Quan-li, DING Wei, et al(徐丰舜，陈全莉，丁 薇，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2021，41(9): 2918.
[15] GAO Jie(高 洁). Superhard Material Engineering(超硬材料工程)，2008，(1): 58.
