Formula: CaMn2+(CO3)2
Anhydrous normal carbonate, dolomite group, forms a series with
dolomite and with ankerite, manganese mineral
Specific gravity: 3.12
Hardness: 3½ to 4
Streak: White
Colour: White, pale rose, pink, light to medium brown
Environments
Kutnohorite occurs typically in hydrothermal deposits associated with manganese-rich sediments, associated with
rhodochrosite, aragonite and
calcite
(HOM).
At the Wutong mine, Guangxi, China, kutnohorite has been found partially coating or completely covering
rhodochrosite
(Minrec 42.6.540-541).
The type locality is Poličany, Kutná Hora District, Central Bohemian Region, Czech Republic.
At the Ryirjima mine, Nagano Prefecture, Japan, magnesian kutnahorite was formed principally as fissure fillings. The major vein
minerals were deposited during a single period of mineralisation in three stages: quartz,
rhodochrosite and finally magnesian kutnahorite
(AM 52.1751-1761).
At the Harlech Dome area, Gwynedd, Wales, UK, kutnohorite occurs in an uplifted area of Cambrian rocks associated with
spessartine, hematite,
magnetite, pyrophanite,
quartz and aluminosilicates. The ore-bed is thought to be a sedimentary-exhalative
hydrothermal deposit, precipitated on the sea-bed at a considerable distance from the fluid source
(MW)
At the the Eldorado Mine, Yankee Boy Basin, Ouray county, Colorado, USA, kutnohorite has been found as tiny crystals and microscopic
crystallised tuffs that partially encrust quartz and
dolomite
(R&M 84.5.423).
At Franklin, New Jersey, USA, kutnahorite has been found in a small veinlet cutting the normal
franklinite ore and bordered by a thin layer of
rhodochrosite
(AM 40.748-760).
Bald Knob, North Carolina, USA, was the source of a sample of kutnohorite from a fine-grained metamorphic rock that equilibrated
under middle amphibolite facies conditions at temperatures of 550
to 600oC
(AM 72.319-328).
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