Niningerite

Niningerite is a rare mineral with the chemical formula (Mn,Mg,Fe)S. It is a sulfide mineral and is known for its opaque, dark gray to black color. The mineral crystallizes in the cubic system, typically forming small, granular masses or individual crystals. The manganese content is dominant, but magnesium and iron are also commonly present, leading to variations in its composition and properties. Niningerite is found in a limited number of geological environments, often associated with meteorites and some metamorphic rocks. Its discovery is linked to meteoritic finds, particularly the Allan Hills 84001 meteorite, which was found in Antarctica. The mineral's name honors Harrison H. Nininger, an American meteorite researcher. Its formation is thought to occur under conditions of high pressure and low oxygen fugacity. Due to its rarity and specific formation conditions, niningerite is primarily of scientific interest to mineralogists and cosmochemists studying extraterrestrial materials and unusual terrestrial mineral assemblages.