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
Specific Gravity6
Colorssilvery white, steel gray, dark gray
Transparencyopaque
Type LocalityYaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China
Mineral Groupsulfides
Usesore of arsenic, minor ore of gold, collector
Associated Mineralsquartz
Rarityuncommon
Description
This specimen features a cluster of well-formed, blocky to prismatic arsenopyrite crystals, displaying a metallic luster and silvery-gray to steel-gray color, with some areas showing tarnish. The arsenopyrite is intergrown with clear to milky quartz crystals and some greenish alteration minerals.
Geological Context
Arsenopyrite is a common hydrothermal mineral found in high-temperature veins, contact metamorphic deposits, and pegmatites. It often forms in association with other sulfide minerals and can be an indicator for gold mineralization.
