| Mineral | ARSENOPYRITE |
| Chemistry | FeAsS |
| Class | Sulfides and Sulfosalts |
| Uses | Important ore of arsenic, minor source of gold and as mineral specimens. |
| Color | Silver-white to steel-grey. |
| Luster | Metallic |
| CrystalSystem | Monoclinic |
| CrystalHabits | include prismatic crystals with a diamond cross section terminated by either a steep dome (actually two of the four faces of a prism) or a less inclined dome, also short stubby crystals doubly terminated with domes.Twinning is common, often bending the crystal and sometimes forming crosses, x s or stars. |
| Fracture | distinct in two directions forming prisms. |
| Hardness | 5½ - 6 |
| Streak | Grey-black. |
| Characteristics | Striations on dome faces, bitter smell when powdered or broken. |
| Occurences | include Kyushu Island and Iname, Japan; Cornwall, England; Bolivia; Freiberg, Germany; Wawa area of Ontario, Canada and Valais, Switzerland. |
| Indicators | crystal habit, cleavage, smell when struck, color and luster. |
| DensityNote | heavier than average for metallic minerals |
| IMAStatus | Approved |
| CellParameters | a = 5.74b = 5.67c = 5.78 β=112.3° |
| Ratio | a:b:c = 1.012 : 1 : 1.019 |
| Strunz | 2/D.22-10 2 : Sulphides D : Sulphides with metal: sulphurselenium and tellurium 22 : Arsenopyrite series |
