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Formula: NiAs
Arsenide of nickel,
nickeline group
Crystal System: Hexagonal
Specific gravity: 7.784 measured, 7.834 calculated
Hardness: 5 to 5½
Streak: Pale brownish black
Colour: Pale copper red
Solubility: Soluble in aqua regia
(Dana
Common impurities: Sb,Fe,Co,S
Environments:
Plutonic igneous environments
Hydrothermal environments
Nickeline is an arsenic-bearing mineral which is a minor component of
nickel-copper
ores in high-temperature hydrothermal veins; it also
occurs disseminated in
peridotite and
norite.
In ore deposits derived from norites nickeline is associated with
pyrrhotite and
chalcopyrite
(Dana).
In vein deposits it is associated with cobalt and
silver minerals
(Dana).
Other associated minerals include skutterudite,
nickelskutterudite,
safflorite,
rammelsbergite,
gersdorffite,
maucherite,
breithauptite,
michenerite,
bismuth and bismuthinite
(HOM).
Localities
At Johanngeorgenstadt, Erzgebirgskreis, Saxony, Germany, nickeline forms crystalline masses and radial aggregates
of zoned composition. It was found fairly commonly in association with
skutterudite,
rammelsbergite, native bismuth
and pitchblende, as well as intergrown with
dolomite, sometimes with feathery
native bismuth. It has been noted further as replacements of
diarsenide (arsenide containing two atoms of arsenic) minerals and
native silver
(MinRec 55.5.614).
At the Belorechensk deposit, Maykopsky District, Adygea, Russia, the deposit includes hydrothermal veins
cross-cutting Paleozoic (541-252 million years ago)
gneisses,
granites,
amphibolites, and
serpentinised
diaphorite.
The oxidation processes are poorly developed mostly in the upper part of the deposit. In the oxidised
parts of dolomite veins with
primary
uraninite,
nickeline, krutovite,
rammelsbergite,
gersdorffite or native arsenic,
the secondary minerals include
limonite, annabergite,
pharmacolite,
picropharmacolite,
hörnesite, rösslerite,
parasymplesite,
nováčekite, gypsum,
aragonite, arsenolite,
schröckingerite and
rabbittite.
In the oxidation zone of the
calcite-baryte veins with
primary galena,
sphalerite, chalcopyrite,
pyrite and marcasite, the
supergene minerals include
limonite, jarosite,
gypsum, melanterite,
brochantite, antlerite,
devilline, serpierite,
anglesite, malachite,
azurite, cerussite,
coronadite, hemimorphite
and native sulphur
(AM 100.336-337).
Nickeline from the Belorechensk deposit -
Image
Nickeline occurs in copper deposits at the Keweenaw peninsula,
Michigan, USA
(Dana).
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