Arsenopyrite
Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
Mineral NameArsenopyrite
Chemical FormulaFeAsS
Mohs Hardness5.5
Crystal Systemmonoclinic
Lustermetallic
Streak Colordark grayish black
Cleavagedistinct on {101}
Fractureuneven to conchoidal
Specific Gravity5.9
Colorssilvery white, steel gray, bronze-yellow, colorless, white, cream
Transparencyopaque
Type LocalityBanská Štiavnica, Slovakia
Mineral GroupSulfides
Usesore of arsenic, collector's specimens, minor ore of gold
Associated Mineralsquartz, dolomite
Rarityuncommon
Description
A striking specimen showcasing metallic, silvery-gray to brassy arsenopyrite crystals embedded within a matrix of granular, cream-colored dolomite, accented by several prominent, clear to milky quartz crystals.
Geological Context
Arsenopyrite commonly forms in high-temperature hydrothermal veins and contact metamorphic deposits, often associated with other sulfide minerals and sometimes gold. Dolomite and quartz are frequently found as gangue minerals in these mineralized environments.
