A mineral inosilicate with composition MnSiO₃. Rhodonite crystallizes in the triclinic system in crystals that are commonly tabular parallel to the base (see illus.). More often it is in cleavable to compact masses or in embedded grains. Crystallographically, rhodonite is closely related to the pyroxenes and thus has two cleavage directions at about 88 and 92°. Hardness is 5.5–6 on Mohs scale, and specific gravity is 3.4–3.7. The luster is vitreous and the color is rose red, pink, or brown. Rhodonite is similar in color to rhodochrosite, manganese carbonate, but it may be distinguished by its greater hardness and insolubility in hydrochloric acid. It has been found at Langban, Sweden; near Sverdlovsk in the Ural Mountains; and at Broken Hill, Australia. Fine crystals of a zinc-bearing variety, fowlerite, are found at Franklin, New Jersey.