In the Hamadan region, Sanandaj-Sirjan Zone (SaSiZ), W Iran, a pegmatite-aplite vein occurs that contains up to 15 vol% sapphire. The Hamadan sapphire is black to blue, and translucent to opaque, which reveals its semi-gem and gem quality. On the basis of petrographic studies, the Hamadan sapphire-bearing pegmatite-aplite vein represents alkali syenitic to syenitic composition and its adjacent granitoids have a range of composition from syenitic to quartz monzonite and granodiorite. New petrographic, whole-rock geochemical data and δ18O values [9.30–12.45‰VSMOW (Vienna Standard Mean Ocean Water)] suggest crustal origin for the peraluminous, S-type and alkaline sapphire-bearing pegmatite-aplite vein. The presence of syngenetic quartz inclusions in the sapphire, and some similar physical-gemological signatures (e.g., parting patterns and angles) of the Hamadan sapphire and kyanite support the generation of the sapphire at the expense of kyanite. In addition, a secondary metasomatic stage may have played a minor role in formation of the sapphire grains. The results indicate an important role for the mafic magmas in triggering crustal anatexis and gem crystallization in continental subduction zone settings.

中文翻译：

---

来自伊朗西部 Alvand 基岩的伟晶岩-阿普莱特矿脉中宝石蓝宝石的岩石成因

在伊朗西部的哈马丹地区，Sanandaj-Sirjan 区 (SaSiZ)，出现了一个伟晶岩-阿普利特矿脉，其中含有高达 15 vol% 的蓝宝石。哈马丹蓝宝石呈黑色至蓝色，半透明至不透明，彰显其半宝石和宝石品质。根据岩相研究，含哈马丹蓝宝石的伟晶岩-阿普里特矿脉代表碱性正长岩至正长岩成分，其相邻花岗岩的成分范围从正长岩到石英二长岩和花岗闪长岩。新的岩石学、全岩地球化学数据和 δ18O 值 [9.30–12.45‰ VSMOW（维也纳标准平均海水）] 表明过铝质、S 型和碱性蓝宝石的伟晶岩-阿普莱特矿脉的地壳起源。蓝宝石中存在同生石英包裹体，以及一些类似的物理宝石学特征（例如，哈马丹蓝宝石和蓝晶石的分离图案和角度）以蓝晶石为代价支持蓝宝石的生成。此外，次级交代阶段可能在蓝宝石晶粒的形成中发挥了次要作用。结果表明，在大陆俯冲带环境中，基性岩浆在触发地壳深熔和宝石结晶方面具有重要作用。