Osmium [Os, 76]

Osmium (Os) is a hard, brittle, transition metal of group 8 in the periodic table of elements and is a member of the platinum group metals (PGMs). It is considered the least abundance stable element in the Earth’s crust, within the range of 0.5–1.0 µg/kg. The highest concentrations of Os are in some igneous rocks and volcanic deposits. Like other PGMs, Os occurs mainly in native alloys of variable composition, and also in Pt ores.