What is Kutnohorite?
Kutnohorite is a manganese-rich carbonate of hydrothermal veins and metamorphic rocks, often recognised by pale pink to brown tones and carbonate cleavage.
Mineralogy and crystal structure
Reference formula: CaMn(CO3)2. Kutnohorite has a trigonal dolomite-group structure and forms a compositional series with dolomite and ankerite. Cation ordering and manganese content can affect colour, density and the selected structural model. Kutnohorite is classified with carbonates and has a trigonal crystal system. Typical hardness is 3.5–4 on the Mohs scale and specific gravity is approximately 3.1–3.2.
Colour, lustre and habit
Typical colours include pink, brown, grey, white. The usual rhombohedral, granular, massive habit and vitreous, pearly, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Kutnohorite forms in or is associated with manganese-rich hydrothermal veins, metamorphic rocks and carbonate ore environments. Important documented localities include the Czech Republic, South Africa, Japan, the United States and Australia.
Soft pink geometry for a carbonate cabinet
Kutnohorite gives a systematic collection a refined colour variation on the dolomite theme. Its muted pink and brown palette looks especially good in a matrix specimen that shows the manganese-rich vein environment.
Collecting and care
Protect rhombohedral cleavage and avoid acids, which rapidly etch carbonate surfaces.
