热处理对阿富汗黄绿色和粉色碧玺颜色的改善
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摘要
采用热处理的方法将阿富汗黄绿色碧玺改善为粉色,优化其外观,并将热处理致色的样品与同产地天然粉色碧玺进行对比,利用大型仪器如红外吸收光谱仪、紫外可见光谱仪、拉曼光谱仪、激光诱导击穿光谱(LIBS)仪、X射线荧光光谱(XRF)仪、X射线光电子能谱(XPS)仪等对其组成、结构以及致色机理进行测试分析,结果表明阿富汗黄绿色碧玺为铁离子和锰离子致色,粉色碧玺为锰离子致色。
Tourmaline,as a kind of beautiful colorful gemstone, is increasingly popular in our life. The price of gemstones is mainly limited by clarity, color, and transparency. The output of high-quality natural tourmalines is getting less and less, thus, finding an alternative way to address the resultant imbalance between supply and demand is paramount. Heat treatment, as a kind of common way to improve the appearance of gemstones, could improve the unattractive color of tourmalines and increase its aesthetic appearance, thereby increasing the prices of tourmalines. Among the different colors of tourmalines, dull yellow-green is an unfavorable color compared with the others. In this paper, we proposed an effective heat treatment approach which can turn such unfavorable color into the beautiful pink, resembling the natural ones. To explore the influences of element type and valence state on the colors of the yellow-green and pink tourmaline and analyze their difference, the tourmaline samples before and after heat treatment were tested by LIBS, XRF and XPS, together with spectra tests like infrared reflectance, ultraviolet reflectance spectroscopy and Raman spectra. On the basis of these results, we further analyzed the mechanism of coloration during heat treatment. The results suggest that the color-causing ions of Afghanistan's yellow-green tourmalines are manganese and iron, while the color-causing ion of pink ones from the same area is manganese. Finally, suggestions for identifying the difference between natural pink tourmalines and manmade pink tourmalines led by heat treatment are given.
Tourmaline,as a kind of beautiful colorful gemstone, is increasingly popular in our life. The price of gemstones is mainly limited by clarity, color, and transparency. The output of high-quality natural tourmalines is getting less and less, thus, finding an alternative way to address the resultant imbalance between supply and demand is paramount. Heat treatment, as a kind of common way to improve the appearance of gemstones, could improve the unattractive color of tourmalines and increase its aesthetic appearance, thereby increasing the prices of tourmalines. Among the different colors of tourmalines, dull yellow-green is an unfavorable color compared with the others. In this paper, we proposed an effective heat treatment approach which can turn such unfavorable color into the beautiful pink, resembling the natural ones. To explore the influences of element type and valence state on the colors of the yellow-green and pink tourmaline and analyze their difference, the tourmaline samples before and after heat treatment were tested by LIBS, XRF and XPS, together with spectra tests like infrared reflectance, ultraviolet reflectance spectroscopy and Raman spectra. On the basis of these results, we further analyzed the mechanism of coloration during heat treatment. The results suggest that the color-causing ions of Afghanistan's yellow-green tourmalines are manganese and iron, while the color-causing ion of pink ones from the same area is manganese. Finally, suggestions for identifying the difference between natural pink tourmalines and manmade pink tourmalines led by heat treatment are given.
引文
[1]黄天平.碧玺充填处理及其鉴定特征研究[M].北京:中国地质大学,2013.
[2]CRISTIANE C,SIGRID G,GERALDO M,et al.Effect of heat treatment on tourmaline from Brazil[J].Physics Chemistry Minerals,2006,33(3):207-216.
[3]罗泽敏,陈美华,赵曦.新疆可可托海碧玺热处理工艺探索及谱学特征[J].宝石和宝石学杂志,2008,10(1):2-6.
[4]CRISTIANE C,ESTER F,NEWTON G,et al.Infrared study of OH sites in tourmaline from the elbaite-schorl series[J].American Mineralogist,2000,85(10):1503-1507.
[5]MENG J P,JIN W,LIANG J S,et al.Effects of particle size on far infrared emission properties oftourmaline superfine powders[J].Journal of Nanoscience and Nanotechnology,2010,10(3):2083-2087.
[6]REDDY B J,FROST R L,MARTENS W,et al.Spectroscopic characterization of Mn-rich tourmalines[J].Vibrational Spectroscopy,2007,44(1):42-49.
[7]FRITZ E,LAURS B.Cat's eye K-feldspar and other chatoyant gems from Tanzania[J].Gems&Gemology,2007,43(2):170-171.
[8]HENN U.Adventures cent oligoclase feldspar from Oregon,USA[J].The Journal of Gemology,2004,29(2):72-74.
[9]LAURS B.Sunstone feldspar from Tanzania[J].Gems&Gemology,2002,38(2):177-178.
[10]LIU X L,FENG X Q.Optical absorption spectra of tourmaline crystals from Altay,China[J].Chinese Optics Letters,2011,9(8):83-85.
[11]刘来宝,何登良.Foitite电气石的热处理及显微结构特征[J].材料热处理学报,2012,32(3):16-21.
[12]钟锐.阿富汗努尔斯坦地区蓝绿色电气石的宝石矿物学研究[M].北京:中国地质大学,2014.
[13]周旭,刘学良,毛荐,等.蓝宝石的改善工艺[J].华东理工大学学报(自然科学版),2013,39(3):296-300.
[2]CRISTIANE C,SIGRID G,GERALDO M,et al.Effect of heat treatment on tourmaline from Brazil[J].Physics Chemistry Minerals,2006,33(3):207-216.
[3]罗泽敏,陈美华,赵曦.新疆可可托海碧玺热处理工艺探索及谱学特征[J].宝石和宝石学杂志,2008,10(1):2-6.
[4]CRISTIANE C,ESTER F,NEWTON G,et al.Infrared study of OH sites in tourmaline from the elbaite-schorl series[J].American Mineralogist,2000,85(10):1503-1507.
[5]MENG J P,JIN W,LIANG J S,et al.Effects of particle size on far infrared emission properties oftourmaline superfine powders[J].Journal of Nanoscience and Nanotechnology,2010,10(3):2083-2087.
[6]REDDY B J,FROST R L,MARTENS W,et al.Spectroscopic characterization of Mn-rich tourmalines[J].Vibrational Spectroscopy,2007,44(1):42-49.
[7]FRITZ E,LAURS B.Cat's eye K-feldspar and other chatoyant gems from Tanzania[J].Gems&Gemology,2007,43(2):170-171.
[8]HENN U.Adventures cent oligoclase feldspar from Oregon,USA[J].The Journal of Gemology,2004,29(2):72-74.
[9]LAURS B.Sunstone feldspar from Tanzania[J].Gems&Gemology,2002,38(2):177-178.
[10]LIU X L,FENG X Q.Optical absorption spectra of tourmaline crystals from Altay,China[J].Chinese Optics Letters,2011,9(8):83-85.
[11]刘来宝,何登良.Foitite电气石的热处理及显微结构特征[J].材料热处理学报,2012,32(3):16-21.
[12]钟锐.阿富汗努尔斯坦地区蓝绿色电气石的宝石矿物学研究[M].北京:中国地质大学,2014.
[13]周旭,刘学良,毛荐,等.蓝宝石的改善工艺[J].华东理工大学学报(自然科学版),2013,39(3):296-300.