Study On The Gemological And Mineralogical Characteristic Of Vanadium Rich Emeralds From Malipo YunNan

On the basis of former studies, this research has tested emeralds form Yun Nan province in China by EPMA, LA-ICP-MS, Infrared Spectroscopy, Ultraviolet and Visible Spectroscopy. A comparative study has been made between emeralds from Yun Nan, China and world’s other vanadium rich emerald deposits.The formation of emeralds from Malipo Yun Nan, Eidsvoll Byrud, Lened Canada,Gandao Pakistan and Salininha Brazil is related to granitic intrusions. Furhtermore,deposits mentioned above in China, Pakistan and Brazil have schist at contact zone.And the deposits in Byrud and Canada have shale and limestone at contact zone respectively.Yun Nan emeralds is generally euhedral and fair transparent. The color of Yun Nan emeralds are mostly light green 、 green and yellowish green. RI:No=1.579~1.587,Ne=1.574~1.580. DR: 0.004~0.008. SG:2.68~2.72. Yun Nan emeralds have solid inclsions as follows : scheelite, fledspar, quartz, fluorite, calcite,tourmaline, arsenopyrite, muscovite, biotite, pyrite, pyrrhotite and chlorite. Compare with the vandium rich emeralds form world other deposits, scheelite arsenopyrite and tourmaline are the characteristic inclusion of Yun Nan emeralds.What’s more, the deep color Yun Nan emeralds have a higher Cr and V content than light color emeralds.Emeralds in Yun Nan from pegmatite veins have a higher content of vandium than emeralds from quartz veins.The element content of Yun Nan emeralds have a raltively wide range, and Yun Nan emeralds have a highest Mg O ratio, above 73%, in the proportion of Fe O,Mg O, Cr2O3 among all vanadium rich emeralds. Chromium is hard to find in Canada emeralds. The monovalent metallic ion and divalent metal ion ratio of Canada emerald is close to 1:1 which is the most matchable to the theoretical value compare to others. The V2O3 content of Byrud emeralds is generally above 1wt.% and it has a highest Cr2O3 content among all rich vandium emeralds. However, the contents of sodium, magnesium and iron in Byrud emeralds is the generally lower than others.Emeralds come from Gandao Pakistan show a high aluminum subtitution which isabout 24%. The contents of sodium, magnesium and iron in these emeralds are usually high especially for sodium and iron which is more than any other vandium rich emerads.Yun Nan emeralds have a high contant of alkalis metal ion which result in a higher content of II typer water than I type water. In the comparison of emeralds from Byrud, Yun Nan emeralds have a absorption at 1600cm-1 and 1633cm-1 which Byrud emeralds do not have. And Byrud emeralds have a absorption at 3607cm-1 Yun Nan emeralds do not.