Osmiridium
Trade name for two materials: osmium, iridium
Very Rare · (Os,Ir)
An old name, with iridosmine, for the natural alloys of osmium and iridium: small, very hard, flat metallic grains that aqua regia leaves untouched. The 1991 nomenclature retired both names; such grains are now native osmium or native iridium according to the leading metal. Tasmania's shallow alluvial workings, Adamsfield above all, were once among the world's main producers, though the whole island gave only 34.7 kg from 1940 to 1945.
Identity
Crystallography
- Crystal system
- Hexagonal
- Habits
- Tabular, Granular, Rounded
- Fracture
- Hackly
Physical properties
- Mohs hardness
- 6.5
- Density
- 21 g/cm³
- Luster
- Metallic
- Colors
- silver-white, steel gray
- Transparency
- Opaque
Geology
- Origins
- Igneous, Sedimentary
- Host rocks
- Ultramafic rock (peridotite, serpentinite), River gravels and sands
- Associated minerals
- Platinum, Osmium, Iridium, Gold, Chromite
- Found in
- Placer deposit
- Geography
- Australia (Adamsfield, Tasmania), Russia (Urals), Canada (Tulameen, British Columbia), South Africa (Witwatersrand)
Classification
- Rarity
- Very Rare
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- Osmiridium. Wikipedia.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Osmium. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Iridium. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Osmiridium: Mineral information, data and localities. mindat.org.
- Native Osmium: Mineral information, data and localities. mindat.org.
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