Rhodochrosite
Catamarca Province, Argentina

This specimen measures 8.5cm in diameter




Rhodochrosite      MnCO3

Carbonate; manganese carbonate, often contains calcium, iron, magnesium, and zinc

Color and Luster: Pink, rose-red, dark red, brown; darkens on exposure to atmosphere; vitreous, pearly; streak white

Hardness: 3.5-4

Cleavage: Perfect in three directions, forming a rhombohedron

Fracture: Uneven, brittle

Crystals: Hexagonal; most often in rhombohedrons, also cleavage masses, granular, compact, botryoidal, incrusting; distinct crystals uncommon

Photo by Lance Kearns


Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals