Glaukosphaerite

glaukosphaerite

paratacamite

malachite

magnesite

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Formula: CuNi(CO3)(OH)2
Anhydrous carbonate containing hydroxyl, rosasite group, nickel-bearing mineral
Specific gravity: 3.78 to 3.96
Hardness: 3 to 4
Streak: Pale green
Colour: Apple-green to malachite-green
Environments

Metamorphic environments
Hydrothermal environments

Localities

In Western Australia glaukosphaerite is apparently an indicator of copper-nickel sulphide mineralisation. Associated minerals include goethite, secondary quartz, paratacamite, gypsum, nickel-bearing varieties of magnesite and malachite, and clays. Glaukosphaerite also fills joints in fresh basic rocks (MM 39.737-743).

At the type locality, Hampton East Location 48, Kambalda Nickel mines, Kambalda, Coolgardie Shire, Western Australia, glaukosphaerite occurs in green spherules of fibres. The nickel mineralisation occurs in greenstone belts that have been invaded by basic to ultrabasic intrusives, also by later porphyries and granites. The whole assemblage has undergone metamorphism of greenschist-facies grade.
Disseminated and massive mineralisation occurs towards the base of a serpentinised dunite unit in a zone of extreme talc-carbonate alteration. Pyrrhotite, pentlandite, chalcopyrite, sphalerite, chromite and traces of galena represent the primary assemblage while violarite, secondary pyrite, and magnetite are characteristic of the zone of supergene enrichment. In the zone of oxidation glaukosphaerite, nickel-bearing malachite, goethite, quartz, manganese oxides, and nickel-bearing chrysotile occur in a weathered talc-rich outcrop (MM 39.737-743).

At St. Ives gold camp, Kambalda, Coolgardie Shire, Western Australia, a specimen was found with a joint coating of green 0.2 mm globules shown to be mainly nickel-bearing malachite with some dolomite layers and a few thin glaukosphaerite zones (MM 39.737-743).

At Widgiemooltha, Coolgardie Shire, Western Australia, glaukosphaerite was first described in 1967, and was determined to be a previously unknown carbonate of copper and nickel, later named glaukosphaerite. Glaukosphaerite was also collected in 1971 in the Widgiemooltha area, at the Dordie North nickel prospect. Here it was intergrown with nickel-bearing celadonite in veinlets in a goethite-quartz-tremolite rock (MM 39.737-743).

At the Scotia Nickel Mine, Bardoc, Broad Arrow Goldfield, Kalgoorlie-Boulder Shire, Western Australia, glaukosphaerite was found as films overgrown with quartz crystals on an antigorite-talc-goethite rock (MM 39.737-743).

The Windarra Nickel Mine, Laverton, Laverton Shire, Western Australia, the scene of the celebrated Poseidon nickel strike in August 1969, has also yielded glaukosphaerite specimens that occur as thin veinlets in a goethite-quartz-chalcedony rock (MM 39.737-743).

At the Carr Boyd Rocks Nickel mine, Menangina Station, Menzies Shire, Western Australia, glaukosphaerite was associated with gypsum on an actinolite rock. Subsequently it was found that the mine and surface dumps are an abundant source of glaukosphaerite in multi-hued green specimens of paratacamite, gypsum, nickel-bearing varieties of magnesite and malachite and clay. A specimen collected in 1972 was composed of green fibres up to 3 mm long on a joint face of a weathered basic rock. The fibres proved to be glaukosphaerite with cores of malachite (MM 39.737-743).

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