Berthierite is a mineral that belongs to the sulfosalt group. It has a metallic luster with blackish to steel gray color. Berthierite is primarily composed of antimony, iron, and sulfur. It has several synonyms, including antimonite, antimonite grey, and Antimonsulfid. Berthierite is commonly found in hydrothermal veins and is associated with other minerals such as arsenopyrite, sphalerite, and pyrite. It has a hardness of 2.5-3.0 on the Mohs scale and a specific gravity of 4.5-5.0. Berthierite is primarily used as a source of antimony, which is used in the production of flame retardants, batteries, and semiconductors.