可爱动物壁纸
Common gem opal: An investigation of micro- to什么的新鲜
nano-structure
期刊名称： American Mineralogist秋岚
作者： Elo Gaillou,Emmanuel Fritsch,Bertha Aguilar-Reyes,Benjamin
Rondeau,Jeffrey Post,Alain Barreau,Mikhail Ostroumov
作者机构： Université de Nantes,Universidad de Michoacán de San Nicolas de Hidalgo,Department of Mineral Sciences
年份： 2008年
阳光大课间
补肾壮阳食物期号： 第11-12期
关键词： Opal-A, opal-CT, common opal, structure, SEM, nanograin
动物的成语有哪些>夜夜歌摘要：The microstructure of nearly 200 common gem opal-A and opal-CT samples from worldwide localities was investigated using scanning electron microscopy (SEM). The opals do not show play-of-color, but are valued in the gem market for their intrinsic body color. Common opal-AG and opal-CT are primarily built from nanograins that average ~25 nm in diameter. Only opal-AN has a texture similar to that of glass. In opal-AG, nanograins arrange into spheres that have successive concentric layers, or in some cas, radial structures. Common opal does not diffract light becau its spheres exhibit a range of sizes, are imperfectly shaped, are too large or too small, or are not well ordered. Opal-AG spheres are typically cemented by non-ordered nanograins, which likely result from late stage fluid deposition. In opal-CT, nanograins aiqs
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