合成钻石的现状及鉴定特征

Status and Identification Characteristics of Synthetic Diamonds

长期以来,合成的黄色及彩色钻石由于其粒度小或者成本高,在商业市场上较为少见。近年来,随着合成钻石技术的发展和突破,合成钻石逐渐进入珠宝市场,为大众所接受。本文通过整合近年来合成钻石的数据及资料,对合成钻石的现状进行了总结和分析,并对比天然钻石的鉴定特征,对市场中存在的高温高压法(HPHT)合成钻石、化学气相沉淀法(CVD)合成钻石及处理合成钻石的鉴定特征作出总结。合成钻石大多具有与天然钻石不同的荧光,如"黑十字"荧光、层状生长纹荧光。HPHT合成钻石的类型主要为Ⅰb型、ⅠaA型、Ⅱa型、Ⅱb型,CVD合成钻石类型主要为Ⅱa型、Ⅰb型,不同的是前者多具有典型的铁或铁镍合金金属触媒包裹体。此外,大部分CVD合成钻石的拉曼光谱在1420cm-1处存在吸收宽带。处理合成钻石与天然钻石更难分辨,需要借助红外光谱、紫外-可见吸收光谱、光致发光光谱(PL光谱)等手段才能准确鉴别。

For a long time, synthetic yellow and other-colored diamonds are relatively rare in commercial market for their small particle sizes or high costs. With the development and breakthrough of synthetic diamond technology, synthetic diamonds have gradually entered the jewelry market and are accepted by the public. This paper summarizes and analyzes the current status of synthetic diamonds by integrating the data of synthetic diamonds in recent years. Compared with the identification characteristics of natural diamonds, it summarizes the characteristics of synthetic diamonds, such as high-temperature and high-pressure synthetic diamonds, chemical vapor deposition synthetic diamonds, and some treated synthetic diamonds in the market. Most synthetic diamonds have different fluorescence from natural diamonds, such as "black cross" fluorescence and layered growth pattern fluorescence. The types of diamonds synthesized by HTHP are mainly Ⅰb, ⅠaA, Ⅱa, and Ⅱb. CVD synthetic diamonds are mainly Type Ⅱa and Type Ⅰb. The difference is that the former has typical iron or iron-nickel alloy metal catalyst inclusions. In addition, the Raman spectrum of most CVD synthetic diamonds has an absorption band at 1420 cm-1. Treated synthetic diamonds are more difficult to distinguish, and they need to be accurately identified by means of IR spectrum, UV-Vis absorption spectrum, and PL spectrum.