Osmiridium, also known as iridosmium or iridosmine, is a natural alloy of osmium and iridium, with traces of other platinum group metals. Osmiridium has been defined as containing a higher proportion of osmium, while iridosmine contains more iridium. However, as the content of the natural Os-Ir alloys varies considerably, the constituent percentages of specimens often reflects the reverse situation of osmiridium describing specimens containing a higher proportion of osmium and iridosmine containing more iridium. In 1963, Max Hutchinson Hey proposed using iridosmine for hexagonal specimens with 80%>Os>32%, osmiridium for cubic specimens with Os<32 nd native osmium for specimens Os>80%. More recently, the Nomenclature Subcommittee of the Commission of New Minerals and Mineral Names, International Mineralogical Association has declared the mineral names osmiridium and iridosmine invalid and to be replaced by iridium and osmium, respectively. Other named naturally occurring alloys of platinum metals have included: iridrhodruthenium, platiniridium, ruthenosmiridium, and rutheniridosmine. The properties of these alloys generally fall between those of the members, but hardness is greater than the individual constituents.