Kutnohorite
A variety of Minerals
What is Kutnohorite?
Kutnohorite is a rare calcium manganese carbonate mineral with magnesium and iron that is a member of the dolomite group. It forms a series with dolomite, and with ankerite. The end member formula is CaMn(CO3)2, but Mg and Fe commonly substitute for Mn, with the manganese content varying from 38% to 84%, so the formula Ca(Mn,Mg,Fe)(CO3)2 better represents the species. It was named by Professor Bukowsky in 1901 after the type locality of Kutná Hora, Bohemia, in the Czech Republic. It was originally spelt "kutnahorite" but "kutnohorite" is the current IMA-approved spelling.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Kutnohorite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Kutnohorite Localities Map
See where Kutnohorite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Key Characteristics
Characteristics of Kutnohorite
Kutnohorite occurs as aggregates of bundled blades of white through rose pink to light brown crystals. Also as simple rhombs with curved faces, polycrystalline spherules and in massive and granular habits. It has perfect rhombohedral cleavage, typical of carbonates. It is brittle with a subconchoidal fracture and it is quite soft, with hardness 3.5 to 4, between calcite and fluorite. Specific gravity is 3.12, denser than both dolomite and calcite. It is soluble in acids, as are all carbonates.
Formation of Kutnohorite
Kutnohorite occurs typically in manganiferous sediments, associated with rhodochrosite, aragonite and calcite. Notable occurrences include Tuscany, Italy and Kutná Hora, Czech Republic. It probably occurs at the Trepča Mines, Stari Trg, Kosovo, in the Balkans. At the Eldorado Mine, Ouray County, Colorado, US, it occurs as tiny white crystals partially encrusting quartz and dolomite. At the Ryujima Mine, Nagano Prefecture in Japan, magnesian kutnohorite occurs with quartz and rhodochrosite. The type locality is Poličany, Kutná Hora, Central Bohemia Region, Bohemia, Czech Republic, and type material is conserved at Harvard University, Cambridge, Massachusetts, US.
Composition of Kutnohorite
The crystal class is trigonal 3, space group R3, the same as for the other members of the dolomite group. There are layers of (CO3)(−2 groups perpendicular to the long crystal axis c, and between these layers there are layers of the cations Ca and Mn. If there were perfect ordering amongst the cations they would separate into different layers, giving rise to the ordered sequence: Ca−(CO3)−Mn−(CO3)−Ca−(CO3)−Mn−(CO3)− along the c axis; not all specimens, however, display such ordering.
Quick Facts
Physical Properties
- Color
- White, pale rose, pink, light to medium brown
- Hardness (Mohs)
- 3.5 - 4
- Density
- 3.15 g/cm³
- Streak
- White
Chemical Properties
- Chemical Formula
- CaMn2+(CO3)2
- Elements
- C, Ca, Mn, O
Also Known As
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Kutnohorite FAQs
How do I identify Kutnohorite?
Kutnohorite can be identified by its hardness of 3.5 - 4 on the Mohs scale, White color. Look for these key characteristics when examining specimens.
What color is Kutnohorite?
Kutnohorite typically appears in White, pale rose, pink, light to medium brown. Color can vary depending on impurities and formation conditions.
How hard is Kutnohorite?
Kutnohorite has a hardness of 3.5 - 4 on the Mohs scale. This gives it moderate hardness.
What is the characteristics of kutnohorite of Kutnohorite?
Kutnohorite occurs as aggregates of bundled blades of white through rose pink to light brown crystals. Also as simple rhombs with curved faces, polycrystalline spherules and in massive and granular habits. It has perfect rhombohedral cleavage, typical of carbonates. It is brittle with a subconchoidal fracture and it is quite soft, with hardness 3.5 to 4, between calcite and fluorite. Specific gravity is 3.12, denser than both dolomite and calcite. It is soluble in acids, as are all carbonates.
What is the formation of kutnohorite of Kutnohorite?
Kutnohorite occurs typically in manganiferous sediments, associated with rhodochrosite, aragonite and calcite. Notable occurrences include Tuscany, Italy and Kutná Hora, Czech Republic. It probably occurs at the Trepča Mines, Stari Trg, Kosovo, in the Balkans. At the Eldorado Mine, Ouray County, Colorado, US, it occurs as tiny white crystals partially encrusting quartz and dolomite. At the Ryujima Mine, Nagano Prefecture in Japan, magnesian kutnohorite occurs with quartz and rhodochrosite. The type locality is Poličany, Kutná Hora, Central Bohemia Region, Bohemia, Czech Republic, and type material is conserved at Harvard University, Cambridge, Massachusetts, US.
What is the composition of kutnohorite of Kutnohorite?
The crystal class is trigonal 3, space group R3, the same as for the other members of the dolomite group. There are layers of (CO3)(−2 groups perpendicular to the long crystal axis c, and between these layers there are layers of the cations Ca and Mn. If there were perfect ordering amongst the cations they would separate into different layers, giving rise to the ordered sequence: Ca−(CO3)−Mn−(CO3)−Ca−(CO3)−Mn−(CO3)− along the c axis; not all specimens, however, display such ordering.
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