Rhodonite - Wikipedia
Rhodonite is a manganese inosilicate, (Mn, Fe, Mg, Ca)SiO 3 and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. It commonly occurs as cleavable to compact masses with a rose-red color (the name comes from the Greek ῥόδος rhodos, rosy), often tending to brown because of surface oxidation.