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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。
A complex fine-grained gem deposit was discovered in western Pakistan. The stone that it produces is characterized by its rich or light green, with the main chromogenic element being chromium. Mineral compositions of such rocks also vary widely within a small range of output, and the gemologist has not yet fully understood their mineral composition (known to include hydrargillite, diopside, aegirine, tremolite , Needle navelite, chlorite, sodium zeolite and sodalite, etc.). In terms of petrology classification, this type of rock is skarn, a type of rock formed after metamorphism of metamorphic rocks, usually calcareous silicate. Sannan is a specific name for skarn produced in this new deposit.