Rhodonite is an often pink or red coloured mineral sometimes polished for use as an ornamental stone. Rhodonite is formed mainly in manganese-bearing metamorphic rocks, especially marble and skarn, which were previously limestone. It is also found in sediments that have been altered by metasomatism. It has the formulae (Mn,Fe,Mg)SiO3 and a relative hardness of 7. Research Rhodonite