Australian sedimentary opal-A and its associated minerals: Implications for natural silica sphere formation
Australian sedimentary opal-A and its associated minerals: Implications for natural silica sphere formation
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DOI：
10.2138/am.2014.4791
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发表时间：
2014-07-01
影响因子：
3.1
通讯作者：
Milke, Ralf
中科院分区：
文献类型：
--
作者：
Liesegang, Moritz;Milke, Ralf
世界市场上绝大多数珍贵的欧泊来自澳大利亚大阿肯托盆地的欧泊领域，这表明非晶二氧化硅以一种导致着名的色彩游戏的方式巩固的非常特殊的先决条件。我们分析了20个蛋白石A样品从安达曼（南澳）和约瓦（昆士兰州）珍贵蛋白石领域，使用岩相显微镜，XRPD，扫描电镜，电子探针识别和表征蛋白石二氧化硅，矿物组合，和主机岩石。Opal-A由平均直径为140-320 nm的亚微米级二氧化硅球体组成。单分散微球的平均粒径为140-290 nm，相对标准偏差（RSD）为
The vast majority of precious opal on the world market comes from opal fields in the Great Artesian Basin of Australia pointing to very special prerequisites for amorphous silica to consolidate in a way that leads to the famous play-of-color. We analyzed 20 opal-A samples from the Andamooka (South Australia) and Yowah (Queensland) precious opal fields, using petrographic microscopy, XRPD, SEM, and EPMA to identify and characterize opaline silica, the mineral assemblage, and the host rock. Opal-A consists of submicrometer-sized silica spheres with an average diameter of 140-320 nm. The average diameter of monodisperse spheres is 140-290 nm with a relative standard deviation (RSD) of