Rhodochrosite, manganese carbonate,
Formula MnCO3.

Crystal system: Trigonal (crystal form usually rhombohedral).
Density: 3.3 to 3.6 gms/cm3
Colour: Pink, red, reddish brown or grey.
Streak: White.

Rhodochrosite is found in hydrothermal veins and in pegmatites, frequently in association with the sulphides galena, sphalerite and pyrite. It is also formed by a metasomatic process in manganese deposits. The finest crystalline specimens come from the Kalahari Manganese Fields and the Sweet Home Mine, Park County, Colorado, USA.

The rhodochrosite specimen pictured comes from the Uchucchaqua Mine, Lima, Peru.

Rhodochrosite from the Uchucchaqua Mine, Lima, Peru