| Arsenic | |
| Formula: | FeAsS (arsenopyrite) |
| Strunz: | 01.CA.05 |
| Dana: | 01.03.01 (Arsenic Group) |
| System: | Monoclinic |
| Class: | Sulphide |
| Symmetry: | Trigonal, hexagonal scalenohedral |
| Colour: | Lead gray, grey, white |
| Habit: | Lamellar, nodular, reniform |
| Cleavage: | Perfect |
| Fracture: | Subconchoidal, uneven |
| Mohs: | 3.5 |
| Streak: | Black |
| Diaphaneity: | Opaque |
| Density: | 5.7 |
The arsenic minerals or arsenic group are a group of trigonal symmetry minerals composed of arsenic-like elements, and one alloy.[1]
The elements are arsenic, antimony and bismuth.[2] The alloy is stibarsen (SbA) an alloy of arsenic and antimony.[3]