Awaruite

awaruite

heazlewoodite

pentlandite

violarite

Images

Formula: Ni3Fe
Alloy, nickel-bearing mineral
Specific gravity: 7.8 to 8.22
Hardness: 5
Streak: Light grey
Colour: Silver-white to greyish white
Magnetism: Strongly magnetic
Common impurities: Co,Cu,S,P,Si
Environments

Plutonic igneous environments
Placers
Metamorphic environments
Meteorites

Awaruite occurs in chromitite associated with ultramafic igneous rocks, in river placers, in serpentinised peridotite, and rarely in meteorites. Associated minerals include gold and magnetite in placers, copper, heazlewoodite, pentlandite, violarite, chromite and millerite in peridotite, and kamacite, allabogdanite, schreibersite and graphite in meteorites (HOM). Awaruite is formed during the serpentinisation of nickel-bearing olivine (Dana).

Localities

At the Lord Brassey Mine, Heazlewood district, Waratah-Wynyard municipality, Tasmania, Australia, a seam of high-grade heazlewoodite ore was encountered with awaruite intergrown with the heazlewoodite (AM 45.450-453).

At the Trial Harbour district, West Coast municipality, Tasmania, Australia, awaruite occurs in association with pentlandite and heazlewoodite (Ramdohr).

At the Lewis Hills Massif, Bay of Islands, Newfoundland, Newfoundland and Labrador, Canada, in harzburgite, dunite, chromitite and orthopyroxenite, rare base-metal phases occur as minute wisps, flecks and grains in serpentine. Awaruite and magnetite are the most common phases identified. Pentlandite, heazlewoodite, awaruite and millerite occur in some dunite. All the base-metal phases are believed to be of secondary origin, related to serpentinisation. Other reactions include the formation of awaruite at the contact between pentlandite and native copper (CM 28.537-552).

At the Jeffrey Mine, Val-des-Sources, Les Sources RCM, Estrie, Quebec, Canada, awaruite is a common accessory phase in most serpentinite of the asbestos-producing belt, and it developed during the serpentinisation process from nickel and iron already present in the rocks. The largest grain of awaruite found measured almost 1 mm across. Magnetite was generally found to be present in the same sections as awaruite, though awaruite was not observed in actual contact with it. There seems little doubt that awaruite and magnetite formed contemporaneously, and repetition of the two-phase assemblages magnetite-awaruite and magnetite-heazlewoodite in different zones suggests an antipathy between awaruite and heazlewoodite (CM 8.519-522).

At the Allende meteorite, Pueblito de Allende, Chihuahua, Mexico, an opaque nodule enclosed in a porphyritic olivine grain in the carbonaceous chondrite comprises 9% by volume of euhedral awaruite, 85% magnetite, 5% pentlandite, and 1% merrillite. The awaruite grains are zoned, with the centres containing more cobalt than the edges (AM 76.1356-1362).

At the type locality, the Gorge River, Westland District, West Coast Region, New Zealand, awaruite occurs in serpentinite (AJM 19.2.29).

Back to Minerals