埃塞俄比亚欧泊充填处理及鉴定特征研究

Study on Filling Treatment and Identification Characteristics of Opal from Ethiopian

埃塞俄比亚WOLLO地区产出的欧泊品种丰富,但火欧泊和水欧泊不稳定,易因外界温度或水分变化形成较多裂纹,严重影响其稳定性及加工性能。因此,本实验对埃塞俄比亚WOLLO地区产出的多裂纹火欧泊、水欧泊样品进行了充填处理,并对充填前、后的样品进行了显微放大观察和红外光谱、相对密度、紫外荧光的测试及分析,总结出了有机充填欧泊的一些鉴定特征。测试及分析结果显示,在2 800～3 100cm-1范围内红外吸收峰为有机充填欧泊的主要鉴定特征,表面及内部显微充填特征、偏小的相对密度、裂隙处的蠕虫状及空洞缺陷处的斑块状强蓝白色荧光可作为辅助鉴定特征。从样品的充填及测试分析结果可见,埃塞俄比亚WOLLO地区产出欧泊的有机充填方案可行,比较明显的开放裂隙易被充填。

A large variety of opals are produced from WOLLO, Ethiopian, but the fire opal and water opal are unstable and easy to crack due to the change of temperature or moisture. Those cracks seriously affect the stability and processing performance of the opals. Therefore, the filling treatment of the fire opal and water opal from WOLLO are studied in this experiment. And then the microscopic magnification observation and specific gravity, UV fluorescence, infrared spectroscopy are also used for test and analysis of the opals before and after the filling treatment. Some identification characteristics for opals with organic filling are summarized. The absorption peaks of the infrared spectrum at 2 800--3 100 cm-1 are the main identification characteristics to distinguish the natural opals from treated samples. And the surface, internal characteristics by filling treatment under microscope, smaller specific gravity, strong blue-white UV fluorescence and worm-like appearance at the cracks could al- so be used as auxiliary identification characteristics. We can conclude from the results anddiscussion in the experiment that the filling treatment of opals are feasible and those open cracks are easily filled.