Formula: Ru
Element, transition metal, platinum group element
Specific gravity: 12.438
Hardness: 6½
Colour: Silver-white
Solubility: Unaffected by air, water and acids (ChC)
Melting point: 2330oC
Boiling point: 4150sup>oC
Abundance in the Earth’s crust: 1 part per billion by mass, 0.2 parts per billion by moles
Abundance in the Solar System: 5 parts per billion by mass, 0.06 parts per billion by moles
Common impurities: Ir,Pt,Rh,Os,Pd,Fe,Ni,Cu

Placer deposits

Ruthenium can exist in many oxidation states, its most common being the oxidation states II, III and IV. It is found free in nature often with the other platinum group metals. Commercially, it is obtained from pentlandite, which contains small quantities of ruthenium (ChC).


In Newfoundland, Newfoundland and Labrador, Canada, Samples of spinel lherzolite, harzburgite, dunite and chromitite from ophiolite complexes in several localities were analyzed for the platinum group elements. Samples of chromitite and dunite show relative enrichment in ruthenium and iridium and relative depletion in platinum and palladium (CM 22.137-149).

At the Semail Ophiolite, Ash Sharqiyah, Oman, chromitite occurs as pods and lenses in dunite hosts within foliated harzburgite and subordinate lherzolite of mantle origin. The chromitite rocks contain traces of the platinum group minerals, in order of abundance, smallest first, rhodium (6 ppm), palladium, platinum, iridium and ruthenium (135 ppm) (CM 20.537-548).

At the type locality, the Horokanai placer, Uryugawa, Uryu District, Kamikawa Subprefecture, Hokkaidō Prefecture, Japan, ruthenium was found included in rutheniridosmine and in platinum in placer deposits derived from ultrabasic rocks (Webmin).

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