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Formula: As4S4
Sulphide of arsenic, paramorph
of pararealgar and realgar (all
three minerals are monoclinic), forms a continuous series with alacránite
Crystal System: Monoclinic
Specific gravity: 3.542 calculated
Hardness: 2½
Streak: Dark orange
Colour: Orange
Environments
Hydrothermal environments
Fumeroles
Coal-seam fires
Bonazziite is a relatively new mineral, approved in 2013. It is associated with low temperature epithermal
mercury - antimony -
bismuth deposits and vapour deposited environments, both burning coal and
volcanic. Common associates include arsenolamprite,
orpiment and realgar.
As realgar (but unlike alacránite), bonazziite alters to
pararealgar in polychromatic and monochromatic light
(Mindat).
Localities
There are two co-type localities, the Alacrán mine, Alacrán, Pampa Larga mining district, Tierra Amarilla, Copiapó
province, Atacama, Chile, and the Khaidarkan Sb-Hg deposit, Batken Region, Kyrgyzstan.
From the Khaidarkan Sb-Hg deposit, Batken Region, Kyrgyzstan, the sample containing bonazziite was not found
in situ, but it is a museum sample, was labelled "wakabayashilite Khaidarkan, Osh Oblast, Kyrgyzstan".
The Khaidarkan Sb-Hg deposit is the type locality for seven other minerals:
chursinite, galkhaite,
khaidarkanite,
kuznetsovite, poyarkovite,
shakhovite and velikite. In the
rock sample, about 4 x 5 x 9 cm3 in size, bonazziite occurs rarely in the intermediate region between
sulphur and realgar in a
calcite matrix. The bonazziite occurs as subhedral to anhedral grains
and shows no inclusions of, or intergrowths with, other minerals. The maximum grain size of bonazziite is about
100 microns. Other spatially associated minerals are wakabayashilite,
alacránite and stibnite
(MM 79.1.121–131).
Bonazziite is a low-temperature hydrothermal mineral probably formed while the system had direct involvement
of magmatic volatiles
(HOM).
At the Ermakovite and Novikovite type locality, Ravat Kishlak, Ayni District, Sughd, Tajikistan,
ermakovite is a fumarolic mineral formed directly from gas from a natural
underground coal fire. Associated minerals include sulphur,
realgar, salammoniac,
alacránite, bonazziite and
thermessaite-(NH4)
(MM 87.1.69–78).
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