坦桑尼亚变色蓝宝石的宝石学特征

陈超洋; 邵天; 黄伟志; 沈澈; 李志彬; 沈锡田

doi:10.15964/j.cnki.027jgg.2020.03.003

坦桑尼亚变色蓝宝石的宝石学特征

1.
中国地质大学珠宝学院, 湖北武汉 430074
2.
北京科技大学土木与资源工程学院, 北京 100083

基金项目:

中国地质大学(武汉)珠宝检测技术创新中心开放基金 CIGTXM-S201808

详细信息

作者简介:
陈超洋(1995-), 男, 硕士研究生, 主要从事宝石学研究

通讯作者:
沈锡田(1962-), 男, 教授, 主要从事宝石学及矿物学研究工作。E-mail：ahshen@foxmail.com

中图分类号: TS93
计量
- 文章访问数: 353
- HTML全文浏览量: 166
- PDF下载量: 54
出版历程
- 收稿日期: 2019-07-08
- 刊出日期: 2020-04-30

Gemmological Characteristic of A Colour-Changed Sapphire from Tanzania

1.
Gemmological Institute, China University of Geosciences, Wuhan 430074, China
2.
School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China

摘要

摘要: 对1颗产自坦桑尼亚Umba具有特殊变色效应的蓝宝石样品进行观察研究, D65光源下显示为浅黄色, A光源下显示为浅紫红色, 长波紫外灯下(365 nm)呈现红色荧光。为研究该样品的内含物种类、微量元素、颜色与变色成因、荧光特性等宝石学性质, 采用显微观察与拍照、激光拉曼光谱仪、傅里叶变换红外光谱仪、激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)和紫外-可见分光光度计测试了该样品。分析发现, 该蓝宝石样品中有片针状的金红石包裹体、成簇的锆石包裹体、尺寸非常微小的高岭石包裹体。蓝宝石样品微量元素主要有Cr、V、Ti、Mg、Fe等, 在可见光区以560 nm为中心的宽缓吸收带导致了变色效应, 结合蓝宝石的电荷补偿理论与微量元素含量, 该吸收带主要由Cr和V产生。根据光致发光光谱与微量元素, 该蓝宝石样品的红色荧光由Cr产生。
- 蓝宝石 /
- 变色效应 /
- 内含物 /
- 宝石学特征 /
- 坦桑尼亚
Abstract: The sample in this study is a sapphire with special colour-chang effect produced in Umba, Tanzania. It shows pale yellow under D65 light source, light purple-red under light source A, and red fluorescence under long-wave UV light (365 nm). In order to study the gemmological characteristics of this sample, including inclusions, trace elements, colour and colour-chang effect, fluorescence characteristics and the other gemmological properties, this sample was tested by microscopic observation and photographing, Raman spectrometer, FTIR spectrometer, laser ablation inductively coupled plasma mass spectrometer and UV-Vis spectrometer. It was found that there are needle-like rutile inclusions, cluster zircon inclusions and very small kaolinite inclusions. The trace elements in the sample are Cr, V, Ti, Mg, Fe, etc. The wide absorption band centered at 560 nm in visible region causes the colour-chang effect. Based on the charge compensation theory of sapphire and contents of trace elements, this absorption band is mainly caused by Cr and V. According to the photoluminescence spectrum and trace elements, the red fluorescence of the sample is produced by Cr.
- sapphire /
- colour-chang effect /
- inclusion /
- gemmological characteristic /
- Tanzania

HTML全文

中国地质大学(武汉)珠宝学院宝石成分及光谱分析室徐行老师在实验测试过程中提供了有帮助的建议，在此表示感谢。

图 1 蓝宝石样品在D65光源下的颜色(a)、A光源下的颜色(b)和紫外荧光灯下的颜色(c) (陈超洋拍摄)

Figure 1. Colour of sapphire sample under D65 light source (a), light source A (b) and ultraviolet fluorescence (c)(Photo by Chen Chaoyang)

下载: 全尺寸图片幻灯片

图 2 变色蓝宝石样品的内含物：聚片双晶纹与管状包裹体(a)；大量针点状包裹体(b)；管状包裹体(c)；羽毛状包裹体(d)；大量片状针状包裹体(e)；聚成簇的晶体包裹体(f) (黄伟志拍摄)

Figure 2. Various inclusions in the colour-changed sapphire sample:Polyflake double grain and tubular inclusion (a); A large number of pinpoints inclusions (b); Tubular inclusion (c); Feathery inclusion (d); A large number of flaky inclusions and needle-like inclusions (e); Clustered crystal inclusions (f)(Photo by Huang Weizhi)

下载: 全尺寸图片幻灯片

图 3 变色蓝宝石样品中金红石包裹体的拉曼光谱

Figure 3. Raman spectrum of rutile inclusion in the colour-changed sapphire sample

下载: 全尺寸图片幻灯片

图 4 变色蓝宝石样品中锆石包裹体的拉曼光谱

Figure 4. Raman spectrum of zircon inclusion in the colour-changed sapphire sample

下载: 全尺寸图片幻灯片

图 5 变色蓝宝石样品的红外光谱

Figure 5. FTIR spectrum of colour-changed sapphire sample

下载: 全尺寸图片幻灯片

图 6 变色蓝宝石样品的紫外-可见光谱

Figure 6. Ultraviolet-visible spectrum of colour-changed sapphire sample

下载: 全尺寸图片幻灯片

图 7 变色蓝宝石样品的光致发光光谱

Figure 7. PL spectrum of colour-changed sapphire sample

下载: 全尺寸图片幻灯片

表 1 蓝宝石样品中的化学成分

Table 1 Chemical composition of sapphire sample

Al₂O₃ /%	MgO /ppmw	P₂O₅ /ppmw	K₂O /ppmw	CaO /ppmw	TiO₂ /ppmw	V /ppmw	Cr /ppmw	FeO /ppmw	Ga /ppmw
99.1	43.6	402	22.0	161	79.6	21.7	40.6	4 720	58.2

下载: 导出CSV

表 2 变色蓝宝石样品中的致色微量元素

Table 2 Trace elements in colour-changed sapphire sample /ppma

Mg	Ti	Fe	V	Cr
22.1	20.3	1 340	8.65	15.9

下载: 导出CSV

参考文献(17)

[1]	Emmett J L, Scarratt K, McClure S F, et al. Beryllium diffusion of ruby and sapphire[J]. Gem & Gemology, 2003, 39(2):84-135. http://www.researchgate.net/publication/238075201_Beryllium_Diffusion_of_Ruby_and_Sapphire?ev=auth_pub
[2]	Moon A R, Phillips M R. Defect clustering and color in Fe, Ti:α-Al₂O₃[J]. Journal of the American Ceramic Society, 1994, 77(2):356-367. doi: 10.1111/j.1151-2916.1994.tb07003.x
[3]	Hänni H A. On corundums from Umba Valley, Tanzania[J]. Journal of Gemmology, 1987, 20(5):278-284. doi: 10.15506/JoG.1987.20.5.278
[4]	Solesbury F W. Gem corundum pegmatites in NE Tanganyika[J]. Economic Geology, 1967, 62(7):983-991. doi: 10.2113/gsecongeo.62.7.983
[5]	Keller P C. Gemstones of East Africa[M]. Tucson:Geoscience Press, 1992:32-41.
[6]	Porto S P S, Krishnan R S. Raman effect of corundum[J]. Journal of Chemical Physics, 1967, 47(3):1009-1012. doi: 10.1063/1.1711980
[7]	Balachandran U, Eror N G. Raman spectra of titanium dioxide[J]. Journal of Solid State Chemistry, 1982, 42(3):276-282. doi: 10.1016/0022-4596(82)90006-8
[8]	Syme R W G, Lockwood D J, Kerr H J. Raman spectrum of synthetic zircon (ZrSiO₄) and thorite (ThSiO₄)[J]. Journal of Physics C:Solid State Physics, 1977, 10(8):1335-1348. doi: 10.1088/0022-3719/10/8/036
[9]	Farmer V C.矿物的红外光谱[M].应育浦, 汪寿松, 李春庚, 译.北京: 科学出版社, 1982: 267.
[10]	Balan E, Lazzeri M, Saitta A, et al. First-principles study of OH-stretching modes in kaolinite, dickite, and nacrite[J]. American Mineralogist, 2005, 90(1):50-60. doi: 10.2138/am.2005.1675
[11]	Lehmann G, Harder H. Optical spectra of di-and trivalent iron in corundum[J]. American Mineralogist:Journal of Earth and Planetary Materials, 1970, 55(1-2):98-105.
[12]	Nikolskaya L V, Terekhova V M, Samoilovich M I. On the origin of natural sapphire color[J]. Physics & Chemistry of Minerals, 1978, 3(3):213-224. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=10.1177/1358863X06076103
[13]	Ferguson J, Fielding P E. The origins of the colours of yellow, green and blue sapphires[J]. Chemical Physics Letters, 1971, 10(3):262-265. doi: 10.1016/0009-2614(71)80282-8
[14]	Gubelin E, Schmetzer K. Gemstones with Alexandrite Effect[J]. Gems & Gemology, 1982, 18(4):197-203. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=JAKO200927161763174
[15]	Shen C, Lu R. The color origin of gem diaspore:Correlation to corundum[J]. Gems & Gemology, 2018, 54(4):394-403.
[16]	陈超洋, 黄伟志, 邵天, 等.特殊变色蓝宝石的紫外-可见光光谱研究[J].光谱学与光谱分析, 2019, 39(8):2470-2473. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gpxygpfx201908026
[17]	Kusuma H H, Astuti B, Ibrahim Z. Absorption and emission properties of ruby (Cr: Al₂O₃) single crystal[A]. Journal of Physics: Conference Series[C].UK: IOP Publishing, 2019.