Arsenopyrite
Formula: FeAsS
Species: Sulfides
Name: Named in 1847 by Ernst Friedrich Glocker for its composition, a contraction of the antiquated term “arsenical pyrite.” Arsenopyrite was known much before 1847 and arsenopyrite, as a name, may be taken as a simple translation of “arsenkies”.
Color: Silver-white to steel-gray, may have a slight yellow appearance
Lustre: Metallic, Sub-Metallic
Hardness: 5½ – 6
Density: 6.07
Crystal System: Monoclinic
Member of: Arsenopyrite Group