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Formula: Ni(OH)2-x(SO4,CO3)0.5x
Sulphate, nickel-bearing mineral
Crystal system: Monoclinic
Specific gravity: 3.30 measured, 3.52 calculated
Hardness: 4
Streak: White
Colour: Emerald-green
Luminescence: No fluorescence under long wave or short wave UV
Solubility: Not attacked by cold hydrochloric or nitric acid
Environments
Metamorphic environments
Hydrothermal environments
Localities
At the type locality, the Otway Ni deposit, Nullagine, East Pilbara Shire, Western Australia, the
nickel minerals occur in shears in
serpentinised
peridotite, and consist mainly of nodular
millerite, polydymite and
pecoraite in a matrix of nickel
carbonates and silicates. The nickel mineralisation is attributed to
hydrothermal and metasomatic activity along the shears, and the
primary assemblage has been subjected to some
supergene alteration due to the effects of weathering.
Paraotwayite has been found in two specimens. Both specimens consist largely of
millerite nodules partly altered to
polydymite, in a matrix of green
nickel-bearing chrysotile.
Cutting across this assemblage are veinlets of dolomite,
gaspéite and, to a lesser extent, paraotwayite.
Paraotwayite occurs as masses of parallel to sub-parallel fibres up to about 0.5 mm long and 5 microns wide.
It is emerald-green in hand specimen, with a silky lustre, and is virtually indistinguishable from
otwayite, which has a similar occurrence
(CM 25.3.409-411).
Paraotwayite from the Otway Ni deposit -
Image
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