The red variety of corundum owes its color and strong fluorescence to the presence of Cr, as well as traces of Fe. The latter can reduce the fluorescence and thus impact the appearance of the final gem. Gem quality rubies are rarely available for scientific study and even less common in their rough form. Opaque inclusions in rubies are often removed during faceting and remain unidentified. This study aims to identify opaque inclusions in rubies from the two most common origins seen in the high end market today: Mogok, Myanmar and Montepuez, Mozambique. Using electron probe microanalaysis (EPMA) the inclusions were identified as sphalerite and pyrrhotite in Mogok rubies. The paragenesis of Myanmar, marble-related rubies is fairly well understood and no Fe-rich minerals apart from sulfides have been identified. Opaque inclusions in Mozambican rubies are a complex mix of Fe-Cu-Ni sulfides with exsolution textures. These inclusions are interpreted to be small amounts of sulfide melt trapped during corundum formation. The different sulfide phases crystallized from this entrapped melt and some phases experienced later exsolution during cooling. The formation of amphibole-related, Mozambican rubies is not well understood, but it is obvious that very different processes are at work compared to the marble-related Myanmar ruby deposits.

中文翻译：

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鉴定来自缅甸莫哥克和莫桑比克蒙特普埃兹的红宝石中的不透明硫化物夹杂物

刚玉的红色变种归因于其颜色和强烈的荧光，这归因于Cr的存在以及痕量的Fe。后者可以减少荧光，从而影​​响最终宝石的外观。宝石品质的红宝石很少可用于科学研究，而以其粗糙的形式则很少见。红宝石中的不透明内含物通常在刻面时被去除，并且未被发现。这项研究旨在鉴定来自当今高端市场中两个最常见来源的红宝石中的不透明夹杂物：缅甸的莫戈克和莫桑比克的蒙特普埃兹。使用电子探针微分析（EPMA）将夹杂物鉴定为Mogok红宝石中的闪锌矿和黄铁矿。缅甸与大理石有关的红宝石的共生作用已被很好地理解，除硫化物外，未发现富铁矿物。莫桑比克红宝石中的不透明夹杂物是具有易溶质地的Fe-Cu-Ni硫化物的复杂混合物。这些夹杂物被解释为在刚玉形成过程中捕获的少量硫化物熔体。从这种截留的熔体中结晶出不同的硫化物相，某些相在冷却过程中随后析出。尚不清楚与闪石有关的莫桑比克红宝石的形成，但很明显，与大理石相关的缅甸红宝石矿床的形成过程截然不同。