Images
Formula: Ni3S2
Sulphide, nickel-bearing mineral
Crystal System: Trigonal
Specific gravity: 5.82 measured, 5.87 calculated
Hardness: 4
Streak: Light bronze
Colour: Light bronze or brass yellow
Solubility:
Common impurities: Fe
Environments
Igneous environments
Hydrothermal environments
Heazlewoodite occurs
in serpentinised dunite and
lherzolite, where
it is probably of hydrothermal origin;
in layered mafic intrusives and chromitite, where it may be a low-temperature
secondary mineral;
in mantle xenoliths.
Associated minerals include andradite, pentlandite,
serpentine, chalcopyrite,
violarite, cubanite,
millerite, mackinawite,
orcelite, zaratite,
shandite, awaruite,
platinum group minerals, magnetite and
chromite
(HOM, Mindat).
Localities
At the type locality, the Lord Brassey mine, Heazlewood district, Waratah-Wynyard municipality, Tasmania, Australia, heazlewoodite
occurs intergrown with magnetite in a band in
serpentine. A very small amount of pentlandite
was present, and the surface of the heazlewoodite was coated with zaratite
(AM 32.484).
At the Alexo Mine, Dundonald Township, Timmins, Cochrane District, Ontario, Canada, heazlewoodite occurs in the
serpentinised peridotite hanging wall of
the old nickel mine. The heazlewoodite occurs as very small yellowish cream grains, in
most cases less than 0.02 mm in diameter.
Pyrrhotite and pentlandite are the principal
sulphides of the ore zone, and magnetite and very minor amounts of
chalcopyrite are also present. Heazlewoodite is restricted to the
peridotite of the hanging wall and co-exists with no sulphide other than
pentlandite. It is sparsely distributed, never exceeding 0.25 per cent in amount
(CM 8.383-385).
In serpentinites of the Eastern Townships, Quebec, Canada,
magnetite occurs as threads between ghost olivine or
pyroxene crystals as discrete grains, or as rims around
primary chromite crystals. It is
invariably in contact with serpentine and commonly associated with either
heazlewoodite or awaruite. Heazlewoodite is a common minor constituent of the
serpentinites, with an average grainsize of about 30 microns. Heazlewoodite
was not observed in the same sections with awaruite, but it accompanies
magnetite in most of the sections in which it occurs. It is suggested that
heazlewoodite
and magnetite formed contemporaneously as by-products of the
serpentinisation process and that they represent an equilibrium assemblage.
Nickel already present in the rocks almost certainly accounts for the
nickel in the heazlewoodite
(CM 8.519-522).
At Miles Ridge, Whitehorse mining district, Yukon, Canada, heazlewoodite is associated with granular
pentlandite. Both minerals are embedded in a spongy mass of
magnetite. The metallic minerals form a veinlet in green
serpentine-like gangue with disseminated
magnetite. The minerals occur in a short stringer of sulphides on the lower
contact of a serpentinised
peridotite dyke, about 200 feet wide and several miles long, which cuts
a series of silicified tuff and
limestone. The rocks near the veinlet are
brecciated and strongly altered to
serpentine and carbonates
(AM 40.692-693).
At the Belvidere Mountain Quarries, Lowell & Eden, Orleans & Lamoille counties, Vermont, USA, heazlewoodite occurs
as pale brass-yellow grains containing minor cobalt,
iron and magnesium, and it is a
primary mineral in the
dunite, in which it is embedded along with many bands and inclusions of
magnetite
(R&M 90.6.538-539).
Back to Minerals