Osmiridio
Osmiridium, also known as iridosmium or iridosmine, is a natural alloy of osmium and iridium, with traces of other metals in the platinum group. It is the alloy with the highest density. In principle it is called osmiridium which contains a higher proportion of iridium, while iridosmine contains more osmium. However, as the content of the natural alloys of Os-Ir varies considerably, the constituent percentages of the specimens often reflect the inverse situation of osmiridium specimens described that contain a higher proportion of osmium and iridosmine containing more iridium. In 1963, Max Hutchinson Hey proposed using the term iridosmine for hexagonal samples with 80% & gt; & Gt; 32%, Osmiridium for cubic samples with Os <32% and native osmium for Os samples> 80% More recently, the Nomenclature Subcommittee of the Commission on the Names of Minerals and New Minerals, International Mineralogical Association has declared the names of mineral osmiridium and iridosmine invalid and to be replaced by iridium and osmium respectively. Other names of naturally occurring alloys of platinum metals have been included: iridrhodruthenium, platiniridium, rutenosmiridium and ruteniridosmine. The properties of these alloys generally fall between those of the members, but of greater hardness than the individual constituents. Deposits
It is found in nature as small, extremely hard, flat metal grains with hexagonal crystalline structure.
Osmiridium is very rare, but can be found in other platinum group mines. There are deposits among other places, in New South Wales and Tasmania, Australia, British Columbia, Canada, the Chinese provinces of Hebei, Sichuan and Tibet, Nova Paka in the Czech Republic, Peyrolles-en-Provence in France, Africa South, Russia and the United States (Alaska, California, Nevada and Oregon).
A very productive mine was exploded on Lake Pedder near Tyenna in Tasmania during World War II the ore was transported by rail from Maydena. The mine is already abandoned and totally covered by a dense natural scrub. It was once one of the world's leading producers of this rare metal, and the Osmiridium recovered mainly in shallow alluvial works. Separation
It can be isolated by adding regal water, which has the ability to dissolve gold and platinum but not the osmium.
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