High Quality Content by WIKIPEDIA articles! Osmiridium, (and iridosmine) are names given to natural alloys of osmium and iridium, with traces of other platinum group metals. Osmiridium has been defined as containing a higher proportion of iridium, while iridosmine contains more osmium. 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, M. H. Hey proposed using iridosmine for hexagonal specimens with 80%>Os>32%, osmiridium for cubic specimens with Os 32% and 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.