一种染色红珊瑚仿制品的宝石学特征及鉴定

Gemmological Characteristics and Identification of a Kind of Dyed Red Coral Imitation

常规的宝石学测定和X射线粉晶衍射以及红外吸收光谱等分析表明,中国珠宝市场上的染色红珊瑚仿制品与天然红珊瑚十分相似。其原料是一种网枝竹节柳珊瑚的造礁珊瑚,矿物成分为方解石型的高镁碳酸钙。电喷雾电离质谱测试分析显示,目前市场上仿制品染色用的有机染料主要有两类:早期采用的是一种分子量约为728的有机物质,这种染色物与天然红珊瑚中的有机物有明显区别,可以作为早期染色红珊瑚仿制品的鉴定依据;晚期采用的是分子量为312.8,326.9,340.9等一系列相差一个"甲基"的有机物质,后者与天然红珊瑚中的有机物较接近,晚期仿真度高的染色红珊瑚仿制品在常规条件下较难与天然红珊瑚区别。

Through the normal gemmological examination and tested by using X-ray powder diffraction analysis, and infrared spectrum analysis, the results indicate that the gemmological characteristics of dyed red coral imitations are very similar to those of the natural ones. The rough material is a sort of Isis reticulate , which is a kind of reef coral. It is composed of calcite-type high-Mg calcium carbonate. Through the electronic spray ionization-mass spectrometry analysis, the results show that there are two categories of the organic dyed materials, one used earlier is the organic substance with the FM of 728, which can be used as a feature to identify the dyed red coral imitation, and the other used later is a mixed material of a series of organic substance with FM of 312.8, 326.9, and 340.9, just lacking of a -CH_2- between them, which is very similar to that of the organic substances in the natural red coral. Therefore, it is more difficult to accurately distinguish the newest-dyed ones from the natural red corals.