Rhodochrosite.

Rhodochrosite.

Rhodochrosite,  MnCO3 is a manganese carbonate mineral, sometimes called mangano calcite. The substitution of calcite for manganese in the mineral leads to a pink coloration. Crystals of rhodochrosite are scalenahedral or rhombohedral, and are usually a deep pink colour. This specimen, from Broken Hill in Australia. is massive, with no crystals present.