Nonninite

Nonninite is a rare mineral composed primarily of calcium, iron, magnesium, and aluminum. Its chemical formula is generally given as (Ca,Fe,Mg)3Al2(Al,Fe)3O12, but variations exist due to the substitution of elements. It belongs to the garnet group of minerals, though it is not a common member of the group. Nonninite was first discovered in the Nonninite massif in the USSR, which is where it gets its name. It typically occurs in metamorphic rocks, often found in association with other high-pressure and high-temperature minerals. The crystals are usually small and can be dark in color, often appearing black or deep red. Its refractive index and density are characteristic of its composition. Due to its rarity, nonninite is not of significant economic importance, but it is of interest to mineralogists for its unique composition and its role in understanding metamorphic processes. Research into nonninite often focuses on its precise chemical variations and its geological context.