不同时期再造琥珀的微细结构对比及鉴定

Comparison and Identification of Reconstructed Ambers Produced in Different Periods Based on Micro-structures

再造琥珀制造技术不断更新换代,并不断取得进展。市场上能见到不同时期的再造琥珀,给实验室鉴定带来挑战。为科学鉴定这些琥珀,结合前人研究和国检(NGTC)近年来的研究成果,主要从放大检查,正交偏光,紫外荧光这三方面分别对早期和近期再造琥珀的鉴定特征进行了系统研究和阐述。结果显示,早期传统再造琥珀的"血丝"状构造明显,其在正交偏光下的特征及紫外灯下的荧光特征明显。近期再造琥珀中的"血丝"变浅,其后多数又进行了一系列后期处理,掩盖了原有的再造琥珀特征,所以其在正交偏光下的特征及紫外灯下的荧光特征均不明显。但在强透射光源照射下,仍可发现局部残余的再造特征,如沿"血丝"分布的片状炸裂纹、流动的"砂糖"状构造等。这些微细结构特征有助于对不同时期再造琥珀进行正确鉴别。

With the increasing development of the manufacturing technology of reconstructed ambers, more and more reconstructed ambers produced in different periods appear in the jewelry market. In order to correctly identify reconstructed ambers, based on the previous studies and research results of NGTC in recent years, this paper investigates and illustrates the micro-structures of reconstructed ambers by using imaging techniques of magnification, crossed polarization, and UV fluorescence. The results show that the traditional reconstruc- ted ambers produced in early period display obvious blood-red streak-like structures, as well as fluorescence features. For the ambers produced recently, the characteristics revealed by magnification and polarization testing are not clear, due to a series of post-processing which could have covered the original features of reconstructed amber. However, some features, such as flaky cracks distributed along the blood-red streaks, flowing granulated sugar-like structure and so on, could be seen by using strong transmitted illumination technique. The reconstructed ambers produced in different periods could be correctly identified by detailed microscopic observation.