Iridium
Species
Very Rare · (Ir,Os,Ru)
Native iridium, the cubic natural alloy of iridium with osmium and ruthenium, silver white with a yellow tinge and among the densest of minerals, as specks exsolved in platinum-iron alloy grains. Known from Nizhny Tagil in the Urals, the Tulameen district of British Columbia and Goodnews Bay, Alaska. Smithson Tennant named the element in 1803, from the insoluble residue of crude platinum, for the rainbow colours of its salts.
Identity
- Formula
- (Ir,Os,Ru)
- Chemical class
- Native element
- Part of
- Osmiridium
- Also known as
- Native iridium
- Ore of
- Iridium
Crystallography
- Crystal system
- Cubic
- Habits
- Cubic, Rounded, Granular
- Fracture
- Hackly
Physical properties
- Mohs hardness
- 6.5
- Density
- 22.7 g/cm³
- Luster
- Metallic
- Colors
- silver-white, gray
- Transparency
- Opaque
Geology
- Origins
- Igneous, Sedimentary
- Host rocks
- Ultramafic rock (peridotite, serpentinite), River gravels and sands
- Associated minerals
- Platinum, Osmium
- Found in
- Placer deposit
- Geography
- Russia (Nizhny Tagil, Urals), Canada (Tulameen, British Columbia), USA (Goodnews Bay, Alaska), South Africa (Witwatersrand), Papua New Guinea (Yodda goldfield)
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.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Iridium. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Iridium. Wikipedia.
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