Spectroscopic Characteristics of Longxi Nephrite From Sichuan and Its Color Genesis
FU Wan-lu1, 2, LU Hao3*, CHAI Jun4, SUN Zuo-yu1
1. School of Earth and Space Sciences, Peking University, Beijing 100871, China
2. State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences), Nanjing 210008, China
3. School of History, Beijing Normal University, Beijing 100875, China
4. School of Archaeology and Museology, Peking University, Beijing 100871, China
Abstract:Sichuan Longxi nephrite is important in ancient Shu (ancient Sichuan) jade culture. In order to get the basic mineral, chemical and spectroscopic characteristics of Sichuan Longxi nephrite with different colors, exploring its significant implications for identifying the jade color and alteration color of nephrite unearthed in Sichuan, lithologic thin section analysis, laser Raman spectroscopy, X-ray fluorescence spectroscopy and μ-XRF scanning were conducted on Longxi nephrite samples with different colors. The systematic field geological survey and sample collection shows that the color bands of Longxi nephrite outcrop have clear boundaries of grey black-green-white-green-gray black. The Longxi nephrite mainly comprises tremolite, containing a small amount of muscovite, calcite, apatite and other accessory minerals. The light bands contain calcite veins, and the dark bands contain relatively more accessory minerals. The Longxi nephrite samples in different colors have almost the same Raman spectra of tremolite with Raman peaks at 174, 228, 376, 392, 674, 935, 1 027, 1 061 cm-1 and the single peak of hydroxyl at 3 675 cm-1 in the range of 3 600~3 700 cm-1. None, characteristic Raman peaks of actinolite or graphite, indicate that the dark color of Longxi nephriteis not from dark-color minerals. The XRF analysis reveals that the main chemical compositions of Longxi nephrite samples are SiO2 (55.20%~57.94%), MgO (24.10%~25.00%), CaO (12.60%~13.80%), Al2O3 (0.39%~1.77%), and iron oxide (0.25%~0.42%). FeO is the main iron oxide tested by the Fe-VOL05 titration method, and there is no significant correlation between the Fe2+ content and the colors of Longxi nephrite. The μ-XRF scanning results indicate that Si and Mg are relatively high in black-deep gray Longxi nephrite, and the contents of V and Cr are relatively high in green-white Longxi nephrite. The contents of common coloring elements in jade,such as Fe, Mn and Cu, do not vary in different color bands of Longxi nephrite.It further proves that V and Cr lead to the green color in Longxi nephrite. The analysis of spectral characteristics and coloring mechanism based on nondestructive identification can be fully applied to the comparative raw material study of ancient jade arte facts, providing scientific data for provenance research on jade material and jade culture of ancient Shu culture.
Key words:Longxi nephrite; Raman spectroscopy; μ-XRF scanning; Color genesis
付宛璐,鲁 昊,柴 珺,孙作玉. 龙溪玉的光谱学特征及颜色成因[J]. 光谱学与光谱分析, 2023, 43(05): 1408-1412.
FU Wan-lu, LU Hao, CHAI Jun, SUN Zuo-yu. Spectroscopic Characteristics of Longxi Nephrite From Sichuan and Its Color Genesis. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(05): 1408-1412.
[1] Wang Chunyun, Zhang Huifen, Ren Guohao. Chinese Journal of Geochemistry (English Language Edition),1990,(2): 182.
[2] XIANG Fang, WANG Cheng-shan, JIANG Zhen-dong, et al(向 芳,王成善,蒋镇东,等). Journal of Earth Sciences and Environment (地球科学与环境学报),2008,(1): 54.
[3] CHEN Jian(陈 剑). Journal of Chinese Culture(中华文化论坛),2009,(S2): 117.
[4] LU Hao, FU Wan-lu, CHAI Jun, et al(鲁 昊,付宛璐,柴 珺,等). Palace Museum Journal(故宫博物院院刊),2021,(9): 123.
[5] YE Shu-xian(叶舒宪). Jade Myth Belief and Chinese Spirit(玉石神话信仰与华夏精神). Shanghai: Fudan University Press(上海:复旦大学出版社),2019. 97.
[6] XUE Lei, WANG Yi-qun, FAN Jian-liang(薛 蕾,王以群,范建良). Journal of East China University of Science and Technology(Natural Science Edition)[华东理工大学学报(自然科学版)],2009,35(6): 857.
[7] WANG Rong(王 荣). Research on the Scientific and Technological Archaeology and Conservation of Early Chinese Jade(中国早期玉器科技考古与保护研究). Shanghai: Fudan University Press(上海:复旦大学出版社),2020. 59.
[8] CUI Wen-yuan, YANG Fu-xu(崔文元,杨富绪). Acta Petrologica et Mineralogica(岩石矿物学杂志),2002,(S1): 26.
[9] JIANG Cui, PENG Fan, WANG Wen-wei, et al(江 翠,彭 帆,王文薇,等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2021, 41(4): 1294.
[10] Liu Y, Zhang R Q, Abuduwayiti M, et al. Ore Geology Reviews, 2016, 72(1): 699.