Geology & Mining

A Mong Hsu ruby in the host rock. The ruby is formed in a vein consisting of corundum, sapphire, ruby, calcite, Mg-chlorite, fuchsite and opaque minerals. The vein itself is embedded in a dolomite marble (area of lower left corner) which shows signs of metamorphic recrystallisation (equal sized dolomite crystals, 2 mm in size). A calcite crystal is shown in reflected light in the figure. It is formed at the border zone of the vein, in contact between the dolomite marble and the ruby. Minerals identified by SEM-EDS analyses. Length of Mong Hsu ruby is 8 mm.