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Formula: Bi4S3
Sulphide of bismuth
Crystal System: Trigonal
Specific gravity: 7.8 measured, 7.97 calculated
Hardness: 2
Streak: Dark grey
Colour: Lead-grey
Luminescence:
Solubility: In concentrated nitric acid ikunolite effervesces and stains grey with dark brown fume;
in FeCl3 it stains brownish red. There is no reaction with hydrochloric acid, HCl, KOH, KCN or
HgCl2
(Mindat).
Environments
Sedimentary environments
Hydrothermal environments
Localities
At Kingsgate, Gough county, New South Wales, Australia, molybdenite,
bismuth and bismuthinite are
the three principal metallic minerals, with galenobismutite,
cosalite, ikunolite,
joseite-A, joseite-B,
pyrrhotite, pyrite,
arsenopyrite, galena,
chalcopyrite, sphalerite,
wolframite and cassiterite
present in minor to trace amounts.
The ikunolite occurs as well developed plates and foliated masses up to 3 cm across, associated particularly
with native bismuth and
molybdenite. Polished section study reveals that ikunolite is
associated with bismuth,
bismuthinite, joseite-A,
molybdenite and gold.
Ikunolite and bismuthinite are commonly intergrown
(AM 47.1431-1433).
At the type locality, the Ikuno Mine, Ikuno-cho-ono, Asago City, Hyogo Prefecture, Japan, ikunolite occurs
in a quartz vein, associated with
ferberite, bismuth,
bismuthinite, joseite,
molybdenite, arsenopyrite,
cassiterite, chalcopyrite
and quartz
(HOM).
Ikunolite from the Ikuno Mine - Image
At the Dolomitic marble quarry, Rędziny, Gmina Kamienna Góra, Kamienna Góra County, Lower Silesian Voivodeship,
Poland, arsenopyrite is the most common ore mineral, and is
accompanied by cassiterite,
pyrrhotite, chalcopyrite,
sphalerite, galena,
stannite, and sulphosalts
aikinite, cosalite,
gustavite, giessenite,
berryite,
tetrahedrite–tennantite,
bournonite and wittichenite.
Bismuth, bismuthinite,
ikunolite, joséite-A and
joséite-B are also essential components of this assemblage.
The ore minerals are disseminated in schist and
amphibolite at contacts with the
dolomitic marble.
Ikunolite has been found in fragments of quartz –
chlorite – arsenopyrite
veins. A typical association includes chalcopyrite,
native bismuth, and aikinite and
friedrichite
in the form of large individual grains reaching about 1 mm in size. They are accompanied by subordinate
ikunolite, bismuthinite,
sphalerite, tennantite and
successive members of the
aikinite-bismuthinite
series up to
gladite. Some ikunolite grains reach 50 microns across, but commonly
they are smaller
(CM 46.5.1305-1315).
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