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Formula: Fe2+(Sb3+)2O4
Antimonite, trippkeite group
Crystal System: Tetragonal
Specific gravity: 4.3 measured, 5.24 calculated
Hardness: 3½
Streak: Brown
Colour: Red-brown to red, black, yellow in transmitted light
Environments
Schafarzikite is a secondary mineral occurring in the
oxidation zones of antimony-bearing hydrothermal mineral deposits. Common
associates include
ankerite, berthierite,
gypsum, kermesite,
quartz, senarmontite,
stibnite and valentinite
(Mindat).
Localities
At the Carma mine, Antonio Quijarro Province, Potosí, Bolivia, the deposit is representative of vein-type
antimony deposits that have
stibnite as the only
mineral of economic interest and a low gold content. The
antimony mineralisation
is bound to a fault zone that cuts dark, fine-grained clastic rocks. The country rocks have been subjected to regional
metamorphism of greenschist facies, during which minute
streaks of pyrite and other base metal sulphides formed. During an early episode
of vein formation, gold occurred in
arsenopyrite at
temperatures above
400oC, and as native
gold containing a little silver at
temperatures above 300oC. The arsenopyrite was converted to
arsenic-bearing pyrite.
Stibnite and antimony sulphosalts
are major stage II minerals in addition to quartz. Fluid inclusions in stage
II quartz indicate a temperature of formation of 130oC to
234oC. Stage III is characterised by an influx of silver-bearing
solutions at temperatures below 360oC, which led to the reaction of
gold
and stibnite to form antimony and
aurostibite. Native gold was
included
by aurostibite during stage III and by
gold-antimony oxides during stage IV.
This inclusion of gold was accompanied by the precipitation of
kaolinite, alunite and
schafarzikite. The temperature of formation of this late-stage deposition is inferred to be
below 72oC. Stage V reflects the adjustment of primary
antimony mineralisation to near-surface conditions by the formation of
stibiconite and goethite
(Economic Geology 90.1.51-66).
At Buca della Vena Mine, Ponte Stazzemese, Stazzema, Lucca Province, Tuscany, Italy, schafarzikite is
associated with apuanite,
versiliaite,
derbylite, bournonite,
pyrite and sphalerite
(HOM).
At the type locality, Krížnica, Pernek, Malacky District, Bratislava Region, Slovakia, crystals, druses, and crusts of
schafarzikite occur on fractures in
quartz-carbonate-stibnite
hydrothermal
ores. The antimony mineralisation is bound to black
shales and phyllites in a
zone of actinolitic rocks. Associated minerals include
ankerite, berthierite,
stibnite, valentinite,
kermesite, senarmontite,
calcite and gypsum. Prismatic crystals
of schafarzikite rarely reach 1.5 millimetres in size and are dark brown to black in colour
(European Journal of Mineralogy 19.419-427, HOM).
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