Spectroscopic Characteristics and Coloring Mechanism of Smithsonite
Jade
LUO Jie1, 2, YUE Su-wei1, 2*, GUO Hong-ying1, LIU Jia-jun3
1. School of Jewelry, Guangzhou City University of Technology, Guangzhou 510800, China
2. Institute of Jewelry, Guangzhou City University of Technology, Guangzhou 510800, China
3. College of Earth Sciences, Guilin University of Technology, Guilin 541006，China
Abstract：There are few studies on the mineralogical characteristics, spectral characteristics and the cause of color of the Smithsonite jade which appears to take on various hues, such as yellow, blue, pink, green, etc. In this paper, yellow-green smithsonite samples were selected and determined by X-ray powder diffractometer (XRD), electron probe (EPMA), laser denudation inductively coupled plasma mass spectrometer (LA-ICP-MS), Fourier infrared transform spectrometer (FTIR), Raman spectrometer (Raman), UV-Vis spectrophotometer (UV-Vis), electron paramagnetic resonance spectrometer (EPR). XRD test results show that the main component of the sample is smithsonite. EPMA test result shows that the main composition of smithsonite is ZnO, with an average content of 61.3%, and the secondary components are CaO, FeO, MnO, CdO and PbO. LA-ICP-MS test result shows that the content of transition elements Fe and Mn in the samples was relatively high, with an average content of 7 363×10-6 and 3 558×10-6, respectively. FTIR spectroscopy analysis showed that there are characteristic peaks of smithsonite, namely 740, 883, 1 490 cm-1, which are caused by in-plane bending vibration, out-of-plane bending vibration and antisymmetric stretching vibration CO2-3. The calcite Raman characteristic shifts of 300, 728, 1 091 cm-1 were shown in every sample caused by the symmetric stretching vibration of ZnO, in-plane bending vibration and symmetric stretching vibration of CO2-3. UV-Vis tests show that the absorption bands around 377, 395 and 417 nm are caused by the 6A1→4E(D), 6A1→4T2(D) transition of Fe3+, and d—d transition Mn2+ were responsible for the yellow-green color of the samples. The EPR spectrum also shows the characteristic six-fold hyper-fine resonance lines of Mn2+ at g=2.0 and Fe3+ at g=1.98. Combined with the results above, it is believed that the yellow-green color of the diamond is caused by the electron transition of Fe3+ and Mn2+d—d orbitals.
Key words：Smithsonite jade; Mineral composition; Component analysis; Spectroscopic characteristics
[1] Frost R L, Hales M C, Wain D L. Journal of Raman Spectroscopy, 2008, 39(1): 108.
[2] Frost R L, Martens W N, Wain D L, et al. Spectrochimica Acta Part A, 2008, 70(5): 1120.
[3] Reddy B J, Yamauchi J, Ravikumar R V S S N, et al. Radiation Effects and Defects in Solids, 2004, 159(3): 141.
[4] LIAO Bao-li, LU Yuan-jie, LI Dong-sheng, et al(廖宝丽, 卢媛杰, 李东升, 等). World Nonferrous Metals(世界有色金属), 2017, (21): 232.
[5] LIU Jia-jun, LUO Jie, YUE Su-wei, et al(刘嘉钧, 罗 洁, 岳素伟, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2021, 41(6): 1936.
[6] YANG Nian, KUANG Shou-ying, YUE Yun-hui(杨 念, 况守英, 岳蕴辉). Journal of Mineralogy and Petrology(矿物岩石), 2015, 35(4): 37.
[7] DU Guang-peng, FAN Jian-liang(杜广鹏, 范建良). Journal of Mineralogy and Petrology(矿物岩石), 2010, 30(4): 32.
[8] WANG Kai, GAN Fu-xi, ZHAO Hong-xia(王 凯, 干福熹, 赵虹霞). Journal of the Chinese Ceramic Society(硅酸盐学报), 2015, 43(2): 205.
[9] WU Rui-hua，WANG Chun-sheng, YUAN Xiao-jiang, et al(吴瑞华，王春生，袁晓江，等). Improvement and Identification of Natural Gemstones(天然宝石的改善及鉴定方法). Beijing: Geological Publishing Press(北京：地质出版社), 1994. 67.
[10] CAO Jun-chen, WEN Gui-lan, WANG Fu-quan, et al(曹俊臣, 温桂兰, 王福泉, 等). Acta Mineralogica Sinica(矿物学报), 1988, (2): 111.
[11] MIN Mao-zhong（闵茂中）. Foreign Uranium and Gold Geology（国外铀金地质）, 1990, (1): 11.
[12] YUE Su-wei(岳素伟). Gems Deposit and Resources(宝玉石矿床与资源). Guangzhou: South China University of Technology Press(广州：华南理工大学出版社), 2018. 272.
[13] LI He, ZU En-dong, YU Jie, et al(李 贺, 祖恩东, 于 杰, 等). Guangxi Light Industry(广西轻工业), 2009, 25(11): 12.
