Polühedrite

Polühedrite is a mineral species belonging to the tetrahedrite group, which are sulfosalt minerals. Its chemical formula is ideally (Cu,Fe)10(Zn,Cd,Fe)2(As,Sb)4S13, although it is often simplified to (Cu,Fe)12As4S13. This means that copper and iron are the primary metallic elements, with zinc, cadmium, and additional iron also present. Arsenic is the dominant non-metal in the anionic structure, though antimony can substitute for it.

Polühedrite is characterized by its complex crystal structure and its varied metallic composition. It typically occurs in hydrothermal veins and associated with other copper and silver minerals. The color of polühedrite can range from dark gray to black. It is opaque and has a metallic luster. Hardness on the Mohs scale is generally between 3 and 4, and its specific gravity is around 4.7 to 5.0.

The mineral is a significant ore of copper and can also contain valuable amounts of silver, arsenic, and antimony. Its formation is usually linked to intermediate to low-temperature hydrothermal processes. Polühedrite is an important mineral in the study of ore deposits and is of economic interest for its metal content. The variability in its chemical formula reflects extensive solid solution between end-members within the tetrahedrite-tennantite series, with polühedrite being characterized by the presence of arsenic.