Hedenbergite

(named after the 19th-century Swedish mineralogist L. Hedenberg), a mineral of the pyroxene group, CaFe(Si₂O₆), hedenbergite often contains a mixture of Mg and Mn²⁺. It crystallizes in a monoclinic system, forming radially fibrous or large rodlike aggregates. Its color is dark green, its hardness is 5.5-6 on the mineralogical scale, and its density is 5,500-6,000 kg/m³. It is found mainly in contact deposits of magnetite and in various calcic skarns. When subjected to weathering it is transformed mainly into siliceous iron ochres.