| Argentopyrite | |
| Category: | Sulfide mineral |
| Imasymbol: | Agpy[1] |
| Strunz: | 2.CB.65 |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | P1121/n |
| Color: | Bronze-brown or gray-white; iridescent (many colors) |
| Habit: | Tabular prisms, pseudohexagonal or pseudo-orthorhombic, possibly pyramidally-terminated |
| Fracture: | Uneven |
| Tenacity: | Brittle |
| Mohs: | 3.5-4 |
| Luster: | Metallic |
| Streak: | Grey |
| Diaphaneity: | Opaque |
| Density: | 4.25-4.27 |
| References: | [2] [3] [4] |
Argentopyrite is a moderately rare sulfide mineral with the chemical formula . It is one of the natural compounds of the type, with M being caesium in very rare pautovite, copper in relatively common cubanite, potassium in rare rasvumite and thallium in rare picotpaulite. The type locality is Jáchymov in Czech Republic. Chemically similar mineral include sternbergite (dimorphous with argentopyrite), lenaite,, and argentopentlandite, .
Although previously assumed orthorhombic,[5] argentopyrite was later shown to be monoclinic, with structural relationship to cubanite. The most important feature of the argentopyrite structure are:[6]