Sapphires from alluvial deposits associated with Cenozoic basalts in Southern Vietnam were collected for investigation of mineral inclusions. In this report, primary iron oxide inclusions were focused on, with detailed mineral chemistry using a Raman spectroscope and electron probe micro-analyzer. Consequently, a variety of iron oxide inclusions were recognized as wüstite, hercynite, and ilmenite. Ilmenite falling within an ilmenite–hematite series ranged in composition between Il_24-30He_36-38Mt_35-40 and Il_49-54He_34-40Mt_7-10, classified as titanomagnetite and titanohematite, respectively. Wüstite with non-stoichiometry, (Fe²⁺_0.3-0.9)(Ti³⁺_<0.179Al³⁺_≤0.6Cr³⁺_<0.1Fe³⁺_≤0.46)☐_≤0.23O, was associated with hercynite inclusions, clearly indicating cogenetic sapphire formation. Wüstite and sapphire appear to have been formed from the breakdown reaction of hercynite (hercynite = sapphire+wüstite) within a reduction magma chamber. Titanohematite and titanomagnetite series might have crystallized during iron–titanium reequilibration via subsolidus exsolution under a slightly oxidized cooling process.

中文翻译：

---

越南南部蓝宝石中氧化铁夹杂物的种类：结晶过程中环境变化的指示

收集了越南南部与新生代玄武岩有关的冲积矿藏中的蓝宝石，以研究矿物包裹体。在本报告中，重点研究了主要的氧化铁夹杂物，并使用拉曼光谱仪和电子探针微型分析仪对矿物进行了详细的化学分析。因此，各种氧化铁夹杂物被认为是辉石，水英石和钛铁矿。属于钛铁矿-赤铁矿系列的钛铁矿的组成范围在Il _24-30 He _36-38 Mt _35-40和Il _49-54 He _34-40 Mt _7-10之间，分别分类为钛磁铁矿和钛铁矿。非化学计量的钨铁矿（Fe ²⁺ _0.3-0.9）（Ti³⁺ _<0.179的Al ³⁺ _≤0.6的Cr ³⁺ _<0.1的Fe ³⁺ _≤0.46）☐ _≤0.23 O，用铁铝夹杂物相关联，清楚地表明同源的蓝宝石形成。辉石和蓝宝石似乎是由还原岩浆室内的海英石（海藻石=蓝宝石+辉石）的分解反应形成的。钛铁矿和钛磁铁矿系列可能在亚钛固溶体在轻微氧化的冷却过程中通过亚固相萃取而在铁钛重平衡过程中结晶。