非洲衣索匹亞Wegel Tena地區新發現的蛋白石研究

2008年衣索匹亞發現新的蛋白石，原石品質很好，但加工時容易破損。磨出成品後，有些品質很好，但有些則耐久性差，甚或彩斑有消失現象。衣索匹亞蛋白石在顯微外觀、折射儀、比重、吸水性等，均與其他產地的蛋白石有很大差異。衣索匹亞蛋白石的彩斑具有合成蛋白石的性質，呈蜂巢狀或蜥蜴皮構造、柱狀彩斑，其折射率(RI＜1.40)和比重(SG＜2.0)也比較低。除了顯微觀察外，本研究以FTIR紅外光譜及X光螢光分析儀等測試衣索匹亞蛋白石，其中紅外光譜是區分衣索匹亞蛋白石與其仿冒品如合成蛋白石、塑膠、玻璃等最好的方法。

關鍵字

紅外光譜； X光螢光分析儀；蜂巢狀構造

並列摘要

An new opal was found in Ethiopia, Africa in 2008. The quality of rough opals from Ethiopia is very good, but they are easily crushed during the ucture as well as prismatic pattern. Ethiopian opals show relatively low refractive index (RI＜1.40) and specific gravity (S.G.＜2.0) with respect to other natural opals. Sophisticated techniques including FTIR and XRF were applied to examine the Ethiopian opals. The FTIR spectroscopy is proven to be the best instrument for the identification of natural opals among their simulation such as synthetic opal, plastic and glass. The play of colors of Ethiopian opal is similar to the synthetic opal, showing honeycomb or lizard-skin structure as well as prismatic pattern. Ethiopian opals show relatively low refractive index (RI＜1.40) and specific gravity (S.G.＜2.0) with respect to other natural opals. Sophisticated techniques including FTIR and XRF were applied to examine the Ethiopian opals. The FTIR spectroscopy is proven to be the best instrument for the identification of natural opals among their simulation such as synthetic opal, plastic and glass.

並列關鍵字

FTIR ； XRF ； honeycomb structure

參考文獻

Benjamin, R.,Fritsch, E.,Francesco, M.,Gauthier, J.P.,Benedict, C.,Eyassu, T.,Eloise, B.(2010).Play-of-color opal from Wegel Tena,Wollo Province, Ethiopia.Gems & Gemology.46(2),90-105.