Spessartine

(from the Spessart range in the Federal Republic of Germany), a mineral of the garnet group, a manganese-containing aluminogarnet having the composition Mn₃AI₂[SiO₄]₃ and containing typical isomorphic impurities of Fe²⁺, Mg²⁺, Ca²⁺, and Y³⁺. Spessartine crystallizes in the cubic system, forming crystals typical of garnets or, frequently, compact granular masses. The color varies, depending on impurities, from light pink to red-brown. The mineral has a hardness on Mohs’ scale of 7–7.5 and a density of 3,800–4,280 kg/m³. Spessartine is most commonly encountered in garnet pegmatites, metamorphic rocks, and skarns.