Tennantite is a mineral that has been known since the 19th century. It is a copper arsenic sulfide mineral that has a bright metallic luster. Tennantite is also known by different names such as tetrahedrite, gray copper ore, and fahleite. Tetrahedrite is a more general term used to describe the copper-antimony-sulfide minerals, while gray copper ore is a less common but still used name. Fahleite, on the other hand, is a type of tennantite that contains zinc and belongs to the tetrahedrite group. All these synonyms are used interchangeably to describe the tennantite mineral.