Rhodochrosite

Rhodochrosite
Chemical composition	MnCO3 + Fe, Ca
Crystal system	Hexagonal
Habit	Rhombohedral
Colors	pink, red, yellowish, gray, brown
Hardness	3.5 - 4
Specific gravity	3.40 - 3.70
Optic nature	Uniaxial -
Refractive Index	1.60 - 1.83
Birefringence	0.208 - 0.220
Lustre	Vitreous to pearly

Spectacular Cabochon 60x30mm Capillitas, Catamarca Province, Argentina Photo courtesy of Barbra Voltaire