赞比亚祖母绿在国内珠宝市场占有重要地位, 具有极高的经济价值, 为丰富该产地祖母绿的溯源信息, 采用常规宝石鉴定仪器, 结合激光拉曼光谱仪、 激光剥蚀电感耦合等离子体质谱仪、 傅里叶变换红外光谱仪、 紫外-可见-近红外光谱仪等测试分析方法, 对赞比亚Kagem矿场所产的祖母绿进行综合测试, 旨在研究Kagem祖母绿的宝石学、 化学成分和谱学特征, 为识别该产地祖母绿特征以及产地溯源提供实际有效的方法。 研究结果表明: 赞比亚Kagem祖母绿样品的颜色呈绿色-蓝绿色, 折射率约为1.580～1.595, 略高于其他产地； 具有弱-中等强度的二色性, 颜色呈蓝绿/黄绿色； 在查尔斯滤色镜下颜色不发生变化； 在长波和短波紫外荧光灯下荧光呈惰性。 放大观察, 可见样品内部含有丰富的固相包裹体, 气液两相包裹体多呈椭圆状或扁条状, 气体体积约占整个包裹体的1/3。 激光拉曼光谱测试显示, 样品中的管状包体为阳起石, 黑褐色金属矿物为磁铁矿, 黑色不规则包体为碳质包体, 柱状包体为钠长石。 化学成分最能凸显赞比亚Kagem祖母绿的产地特征, 与其他产地相比, Kagem祖母绿的致色元素表现为富Cr贫V, 化学成分特征为高Fe、 高Mg和高碱金属元素。 分析红外光谱可知, 该产地祖母绿中Ⅰ型水的特征吸收峰主要在7 268和7 140 cm-1处, Ⅱ型水的特征吸收峰主要在7 075、 6 840、 5 340、 5 205和1 619 cm-1处, Ⅱ型水的红外吸收峰整体强于Ⅰ型水, 表明Ⅱ型水的相对占比大于Ⅰ型水, 这一特征可与贫碱结构水类型的祖母绿产地相区分。 祖母绿的紫外-可见-近红外吸收光谱主要由Cr3+、 Fe2+和Fe3+的吸收峰构成, 吸收峰的峰位和吸收强度在不同方向上略有差异。

The emeralds from Zambia, with high economic value, occupy an important position in the domestic jewelry market. In order to enrich the traceability information of emerald origin, a comprehensive test of emeralds from the Kagem mine in Zambia was conducted using conventional gemological identification instruments, combined with test and analysis methods such as laser Raman spectroscopy, laser exfoliation inductively coupled plasma mass spectroscopy, Fourier transforms infrared spectroscopy and UV-Vis-NIR spectroscopy, to study the gemological, chemical composition and spectroscopic characteristics of the Kagem emeralds and providing practical and effective methods for identifying the characteristics and origin tracing of the emeralds from the origin. The results show that the emerald samples from the Kagem mine ranged from green to blueish green. The refractive index was higher than other origins, and varied from 1.580 to 1.595. The emeralds from the Kagem mine were typically inert to long- and short-wave UV radiation. The emeralds showed no reaction under the Chelsea filter. Dichroism was medium yellowish green and bluish green. Magnified observation shows that the emeralds contained abundant solid-phase inclusions inside. The gas-liquid two-phase inclusions are mostly elliptical or flat strips, and the gas volume accounts for about one-third of the inclusions. Laser Raman spectroscopy shows that the tubular inclusions were actinolite, the black-brown metallic minerals were magnetite, the black irregular inclusions were carbonaceous, and the columnar inclusions were albite. The chemical composition of emeralds distinguishes Kagem from other areas of origin. Compared to other origins, Kagem emeralds exhibit chromogenic elements rich in Cr and poor in V. There are high Fe, high Mg and high alkali metal elements in Kagem emeralds. The infrared spectra show that the characteristic absorption peaks of type Ⅰ water in emeralds of this origin were mainly at 7 268 and 7 140 cm-1, and the characteristic absorption peaks of type Ⅱ water were mainly 7 075, 6 840, 5 340, 5 205, and 1 619 cm-1. The IR absorption peaks of type Ⅱ water were stronger than those of type Ⅰ water, indicating that the relative proportion of type Ⅱ water was greater than that of type Ⅰ water. This feature can be distinguished from the emerald with poor alkali. The UV-Vis-NIR absorption spectra of emeralds were related to Cr3+, Fe2+ and Fe3+, and the positions and intensities of the absorption peaks were different in different directions.