Comparative Study On Locality Features Of Emerald In Yunnan And Which In Other Areas Of The World

In this paper, the author compared used Ultraviolet-visible-Near Infrared Spectroscopy, FTIR,Raman spectrum, LA-ICP-MS techniques to study the locality feature of Yannan, Nigeria and Zambia samples.The major conclusions are as follows:The LA-ICP-MS testing on the emerald of these three gem-mining regions shows that these emeralds take place ion substitution in some degree. The Zambia emerald is in a high degree and the Nigeria one is the lowest. Meanwhile, the comparison between the coloring elements Cr and V by bar graph indicates that the content of V in Yunnan emerald is much higher than that in Nigeria and Zambia emerald, but the content of Cr in the latter is absolutely higher than that in Yunnan emerald. Morever, on the bases of the comparison of microelements by bar graph, it arrives a conclusion that the content of Ga and Sc in Yunnan emerald is obviously lower than the emeralds in other two regions, on the contrary, the content of Mn and Cs is a lot higher. This offers solid evidence for identifying Yunnan emerald.Through the ultraviolet-visible light absorption spectrums testing, it is known that the emerald absorbs at yellow-red light and purple light, and the absorption peaks of emerald in Yunnan is at 386、429、619.5、684nm, different from thoes samples in other origins. Among them, the absorption at 386nm belongs to Fe³⁺ , and the absorption at 429、619.5nm is the result of Cr³⁺ and V³⁺.The IR characteristic are similer in emerald, thus it’s hard to be a way to indentify emerald’s origins.Resulting from LRS testing, the bands of Yunnan emerald is at 321cm^-1、421cm^-1、445cm^-1 , the bands of Nigeria emerald is at 188cm^-1、217cm^-1、245.8cm^-1、273cm^-1、291.7cm^-1、421cm^-1、444cm^-1、527cm^-1、573cm^-1、584cm^-1 , and the Zambia one is at 324cm^-1、398cm^-1、524cm^-1、685cm^-1、1009cm^-1 . In addition, the bands at 400cm^-1 belongs to VAl-O、δAl-O ; near 525cm^-1 belongs toδO-Be-O ; at 685cm^-1 belongs to VSi-O-Si ; near 1010cm^-1 belongs to VBe-O , and at 1066cm^-1 belongs to VSi-O .