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Formula: Bi5S4
Sulphide of bismuth,
tetradymite group
Crystal System: Trigonal
Specific gravity: 7.815 calculated
Hardness: 2 to 2½
Colour: Silvery
Environments
Volcanic igneous environments
Hydrothermal environments
Zipserite is a new mineral, approved in 2022.
Localities
At the type locality, the Alsó-Rózsa adit, Nagybörzsöny, Szob District, Pest County, Hungary, zipserite, a new
bismuth
chalcogenide, was found in samples with
bismuth sulfotellurides, taken from
the tailings pile of the adit. Hydrothermal base-metal and precious metal mineralisation are developed in this deposit
in andesites to dacites of
Miocene age (23.03 to 5.3 million years ago). The mineralisation forms veins in
andesitic rocks but changes to veinlet zones and disseminations in
dacites. The dump material is formed by intensively hydrothermally altered
volcanic rocks. The main alteration is propylitisation, which results
in the original rocks being changed into a mixture of predominantly white sheet silicates with disseminated sulphides
and sulphosalts. Two stages of mineralisation were distinguished: the first stage is represented by
pyrite, galena,
sphalerite, chalcopyrite and
pyrrhotite, and the second one mainly by
arsenopyrite, bismuth,
bismuthinite, sulphosalts, gold,
baryte and carbonates. Pilsenite,
ikunolite, tetradymite,
joséite-A and joséite-B are
present, in addition to other gold - silver
- bismuth - tellurium minerals such
as jonassonite, petzite,
hessite and jaszczakite.
The specimens that contain zipserite also contain abundant
bismuthinite and native bismuth,
and rare ikunolite and joséite-A.
Zipserite is located particularly along the contact between bismuth and
bismuthinite, suggesting that it may be a reaction product of these two
minerals. Zipserite forms large inclusions up to 500 μm; some of these inclusions seem to be subhedral, lath-like
crystals. The colour is silvery, identical to the colour of bismuthinite,
with a metallic lustre
(MM 88.482–492).
Zipserite from the Alsó-Rózsa adit -
Image
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