红外光谱和拉曼光谱在热处理海蓝宝石鉴定中的应用  

Application of Infrared Spectroscopy and Raman Spectroscopy on Identification of Heat-treated Aquamarine

作　　者：杨如增[1] 杨松[1] 

机构地区：[1]同济大学海洋与地球科学学院,上海200092

出　　处：《宝石和宝石学杂志》2014年第1期46-49,共4页Journal of Gems & Gemmology

基　　金：国家自然科学基金项目(49772096)

摘　　要：在适当的热处理条件下,黄绿色绿柱石能够转变为理想颜色的海蓝宝石。天然海蓝宝石与热处理海蓝宝石的价格差异较大,因此探索热处理海蓝宝石的诊断性鉴定特征就显得十分必要。对不同温度下热处理海蓝宝石进行傅里叶变换红外光谱和激光拉曼光谱的测试分析,结果发现,当热处理温度超过400℃后,随着加热温度的升高,在红外光谱中由[Fe2(OH)4]2+伸缩振动引起的3 233cm-1处吸收谱峰明显减弱,直至消失。5 268cm-1附近由水伸缩和弯曲振动引起合频区的吸收带由尖峰变得宽缓;8 700,6 818cm-1两处水吸收峰的相对强度也随着加热温度升高而减弱。热处理海蓝宝石Si-O-Si伸缩振动产生的在682,3 604cm-1处的拉曼光谱谱峰强度随着加热温度升高逐渐减弱,1 070cm-1处的拉曼峰强度明显降低。经700℃加热后,拉曼光谱基线明显向上方漂移。这些光谱特征变化对热处理海蓝宝石的鉴定有重要意义。Experiments show that yellow-green beryls can be transformed into aquamarines by using appropriate heat treatment. However, in jewelry market, the price of natural aqua- marine is quite different from that of heat-treated aquamarine. Thus exploring diagnostic i- dentification characteristics of heat-treated aquamarine is of great importance. Previous iden- tifications of heat-treated aquamarine were their internal inclusion characteristics, which were observed through microscope. However, it was difficult to identify flawless aquamarines. The authors selected some samples from Altay to treat under a reducing atmosphere at differ- ent temperatures for 3 hours. Fourier transform infrared spectrometer and Raman spectros- copy were used to explore the characteristic absorption peaks of the heat-treated samples. The results show when the heating temperature is above 400°C, the peak caused by the stretching vibration of [Fe2 （OH）4]2＋ at 3 233 cm-1 is significantly reduced or even disap- peared and the sharp absorption peak around 5 268 cm-1 caused by H20 becomes wide andgentle. The relative intensity of absorption peak at 8 700 and 6 818 cm 1 caused by H20 weakens as the heating temperature is elevated. It is found that the Raman spectral intensity at 682 and 3 604 cm 1caused by stretching vibration of Si--O--Si reduce as the heating tem- perature rises, and spectral intensity at 1 070 cm-1 decreases. After heat treatment at 700~C, the baseline of Raman spectrum drifts upward obviously.

关 键 词：红外光谱 拉曼光谱 热处理 海蓝宝石 

分 类 号：TS93[轻工技术与工程]