Arsenopyrite
Species
Common · FeAsS
Iron arsenic sulfide and the most common arsenic mineral. Forms in high-temperature hydrothermal veins and metamorphic rocks. Often associated with gold deposits. Produces a garlic odour when struck due to arsenic vapour release.
Identity
- Formula
- FeAsS
- Chemical class
- Sulfide
- Also known as
- Mispickel, Arsenical pyrite
Crystallography
- Crystal system
- Monoclinic
- Habits
- Prismatic, Massive, Granular
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 5.5
- Density
- 6.07 g/cm³
- Luster
- Metallic
- Colors
- silver-white, steel gray
- Streak
- gray-black
- Transparency
- Opaque
Geology
- Origins
- Hydrothermal, Metamorphic
- Host rocks
- Granite, Schist and gneiss
- Associated minerals
- Pyrite, Gold, Chalcopyrite, Sphalerite
- Found in
- Hydrothermal vein (lode)
- Geography
- worldwide
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Arsenopyrite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Arsenopyrite: Mineral information, data and localities. mindat.org.
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