68 / 2019-10-06 13:31:00

黑青黑碧的谱学鉴别特征初探

关键词：黑青 黑碧 近红外光谱 谱学特征

稿件ID：868290
黑青黑碧的谱学鉴别特征初探
代路路，杨明星
（中国地质大学珠宝学院，湖北 武汉 430074）
摘要：黑青指颜色近黑色，主要成分为透闪石的青玉。黑碧指颜色近黑色，主要成分为阳起石的碧玉。本文通过电子探针、激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)、X射线粉晶衍射对其化学成分和矿物种类进行区分。拉曼光谱测试显示黑青为标准透闪石峰位，黑碧的主峰位有几个波数的偏差，向波数小的方向移动，原因可能是Fe含量造成的，黑青TFeO=2.21%～2.98%，黑碧TFeO=8.12%。显微紫外-可见分光光度计透射法测试得出在400～800nm处，黑青450、680nm有吸收带，归属于Fe的作用；黑碧450nm有吸收带，归属于Fe的作用，660、690nm附近有宽的吸收带，归属于Cr3+的作用。显微紫外-可见分光光度计测试范围可到近红外区域，黑青在1397、1915、2120、2130、2388、2465nm处有吸收带，黑碧在1400、2313、1394nm处有吸收带。通过查阅文献得，软玉中1390～1420nm为OH＋H2O二者合成峰，1915nm附近强吸收峰以及附近的弱吸收峰为水分子弯曲振动与伸缩振动吸收峰组合频，2210～2300nm归属Fe-OH吸收作用，2300～2400nm归属Mg-OH吸收作用。对样品进行近红外光谱透射法测试得出结果，黑青以HQ-1为例：5224cm-1（1915nm）、4738 cm-1(2120nm)、4349cm-1,4317cm-1(2310nm)、4190cm-1(2388nm)、4064cm-1(2465nm)有吸收峰；黑碧以MQ为例4708cm-1(2124nm)、4308cm-1(2313nm)、4178cm-1(2394nm)有吸收峰，测试结果与显微紫外-可见分光光度计保持一致。由近红外谱学特征可初步得出黑青黑碧的谱学鉴别特征。
关键词：黑青 黑碧 近红外光谱 谱学特征

Preliminary Study on the Characteristics of Spectral Identification of Heiqing and Heibi
DAI Lulu，YANG Mingxing
（Gemmological Institute，China University of Geosciences，Wuhan 430074，China）　
Abstract: Heiqing refers to dolomite-related nephrite with the color of the nearly black whose main component is tremolite. Heibi refers to serpentinite-related nephrite with the color of the nearly black whose main component is actinolite. In this paper, the chemical composition and mineral species are distinguished by EPMA, LA-ICP-MS and XRD. Through Raman spectroscopy test, Heiqing is the standard tremolite peak position, while the main peak position of Heibi has several wavenumber deviations, which move in the direction of small wavenumber. The reason may be caused by Fe content, the Fe content of Heiqing (TFeO=2.21%～2.98%) is higher than that of Heibi (TFeO = 8.12%). Through the transmission test of micro-UV-visible spectrophotometer, it is found that there are absorption bands at 450, 680 nm of Heiqing at 400～800 nm, which attributed to the role of Fe. Heibi have 450 nm absorption bands and attributed to the role of Fe, and there are 660, 690nm near a wide absorption band, attributed to the role of Cr3+. The micro-ultraviolet-visible spectrophotometer can be tested in the near-infrared region, Heiqing have absorption bands at 1397, 1915, 2120, 2130, 2388, and 2465 nm, while Heibi has absorption bands at 1400, 2313, and 1394 nm. According to the literature, the 1390～1420nm in nephrite is the synthesized peak of OH+H2O, the strong absorption peak near 1915nm and the nearby weak absorption peak are the combined frequency of water molecule bending vibration and stretching vibration absorption peak, and 2210～2300nm attributed to the role of Fe-OH, 2300～2400nm attributed to the role of Mg-OH. The sample was subjected to near-infrared spectroscopy transmission test, and the test results suggest that Heiqing have 5224 cm-1 (1915 nm), 4738 cm-1 (2120 nm), 4349 cm-1, 4317 cm-1 (2310 nm), 4190cm-1 (2388nm), 4064cm-1 (2465nm) absorption peaks taking as an example of HQ-1, Heibi have 4708cm-1(2124nm), 4308cm-1 (2313nm), 4178cm-1 (2394nm) with absorption peaks taking as an example of MQ. And the test results are consistent with the micro-ultraviolet-visible spectrophotometer. From the near-infrared spectroscopy characteristics, the spectral identification characteristics of Heiqing and Hebi can be preliminarily obtained.
Key words: Heiqing; Heibi; near-infrared spectroscopy; spectral characteristics

1. 红外光谱分析

图1.1黑青近红外吸收光谱
Figure 1.1: Near-infrared absorption spectrum of Heiqing

图1.2.黑碧近红外吸收光谱
Figure 1.1: Near-infrared absorption spectrum of Heibi

2.显微紫外-可见光谱分析

图2.1黑青可见-近红外吸收光谱
Figure 2.1: visible-near infrared absorption spectrum of Heiqing

图2.1黑碧可见-近红外吸收光谱
Figure 2.1: visible-near infrared absorption spectrum of Heibi