巴基斯坦的宝玉石新品种: 山南矽卡岩(Sannan-Skarn)

A New Deposit of Complex Fine-Grained Rocks from Western Pakistan:Sannan-Skarn

  • 摘要: 在巴基斯坦西部发现了一种复杂的细粒宝玉石矿床。其产出的石材以其或浓或淡的绿色为特征,主要致色元素为铬。此类岩石的矿物组成在小的产出范围内亦有很大的变化,珠宝学家尚未完全了解其组成矿物(已知包括水钙铝榴石,透辉石,霓石,蓝透闪石,针纳钙石,绿泥石,钠沸石与方钠石等等)。以岩石学分类论,该类岩石为矽卡岩,一种经原岩交代变质作用后形成的岩石,通常为钙质硅酸岩。山南(Sannan)是产于此新矿床的矽卡岩的特定名称。

     

    Abstract: A new deposit of complex fine-grained rocks was found in Western Pakistan. The material is characterised by its more or less green colour, due to chrome. The mineral components vary strongly in short distances and the minerals (hydrogrossular, diopside, aegirine, winchite, pectolite, chlorite, natrolite, sodalite etc.) are not well known by gemmologists. A common term to name the material is skarn, as it describes a rock formed by metasomatic replacement of a parent rock, commonly a calc-silicate rock, transformed in a metamorphic process. Sannan is a specific modifier that specially describes the skarn from the new occurrence.

     

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