Wittichenite

Wittichenite is a copper bismuth sulfide mineral with the chemical formula Cu3BiS3. It belongs to the sulfosalt group of minerals and is known for its distinctive metallic luster and pale brass-yellow to steel-gray color. It typically occurs as small, granular masses or as an accessory mineral in hydrothermal ore veins. Wittichenite is relatively soft, with a Mohs hardness of 3 to 3.5, and has a specific gravity of around 5.1.

This mineral was first discovered in the Wittichen mine in the Black Forest region of Germany, from which it derives its name. It is often found in association with other copper and bismuth minerals, such as bismutinite, native bismuth, chalcopyrite, and galena. While not a significant ore of copper or bismuth, wittichenite is of interest to mineral collectors and geologists studying ore-forming processes. Its crystallography is monoclinic, and it can form small prismatic or tabular crystals, although massive aggregates are more common. Microscopic examination often reveals characteristic twinning and intergrowths with other minerals. Wittichenite is relatively rare and found in scattered locations worldwide, primarily in hydrothermal deposits.