corundum, sources.12, Thailand.12, Bo Ploi, inclusions.5, gems

Three main types of fluid inclusions occur in Bo Ploi sapphires: (1) vapor-rich CO₂ with a density up to about 0.86 g/cm³; (2) multiphase inclusions containing several daughter minerals, hypersaline brine, and a CO₂-rich vapor phase; and (3) (silicate?)-melt inclusions with immobile vapor bubbles in an isotropic or weakly anisotropic phase of low relief, with bubbles becoming mobile when heated above 800 °C. These observations suggest a magmatic origin for the sapphires, although they did not crystallize as phenocrysts within the basalts that transported them to the surface.