Famatinite
Famatinite is a sulfosalt mineral with the chemical formula copper antimony sulfide (Cu3SbS4). It belongs to the sulfosalt class of minerals and is classified in the Strunz system as 2.KA.10. The mineral crystallizes in the monoclinic crystal system. It typically exhibits a metallic luster and a dark gray to black color. With a hardness of approximately 2.5 to 3 on the Mohs scale and a relatively high density, famatinite is not commonly encountered in mineral collections due to its rarity and limited occurrence.
Composition
- CuCopper43.3%
- SSulfur29.1%
- SbAntimony27.6%
Overview
Famatinite is a sulfosalt mineral with the chemical formula copper antimony sulfide (Cu3SbS4). It belongs to the sulfosalt class of minerals and is classified in the Strunz system as 2.KA.10. The mineral crystallizes in the monoclinic crystal system. It typically exhibits a metallic luster and a dark gray to black color. With a hardness of approximately 2.5 to 3 on the Mohs scale and a relatively high density, famatinite is not commonly encountered in mineral collections due to its rarity and limited occurrence.
Etymology
Famatinite is named after Cerro General Belgrano, the type locality in the Famatina Mountains of Argentina, where it was first discovered.
Occurrence
Famatinite is known only from the type locality in the Famatina Mountains, Argentina, where it occurs in association with other sulfide minerals in a hydrothermal environment.
How to recognize it
Famatinite can be identified by its metallic luster, dark gray to black color, and relatively low hardness of 2.5 to 3 on the Mohs scale. It does not leave a distinct streak and is typically found in small grains or aggregates. Due to its rarity and similar appearance to other sulfide minerals, it is often confused with minerals such as chalcopyrite or other copper sulfides without detailed chemical analysis.
Host rocks
Famatinite is typically found in hydrothermal veins, associated with sulfide mineral assemblages in altered igneous or metamorphic rocks.
Trivia
Famatinite is notable for its unique chemical composition, combining copper, antimony, and sulfur in a rare sulfosalt structure. It is one of the few minerals named after a specific mountain range, the Famatina Mountains in Argentina. Additionally, it is a grandfathered mineral, meaning it was recognized by the IMA before the formalization of modern mineral classification standards.