Manganoan Calcite
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/14730981@N08">James Petts</a> from London, England (CC BY-SA 2.0)
Mineral NameManganoan Calcite
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Streak ColorWhite
CleavagePerfect rhombohedral in three directions
FractureConchoidal to uneven
Specific Gravity2.71
Colorspink, pale pink, salmon, white
TransparencyTranslucent
Type LocalityWorldwide (notably Peru, Mexico, USA for pink varieties)
Mineral GroupCarbonates
Usescollector's specimens, ornamental stone
Associated Mineralsquartz, fluorite, sulfides, other carbonates
Rarityuncommon
Description
This specimen features pale pink to salmon-colored manganoan calcite crystals, forming bladed aggregates with a vitreous to pearly luster, often in a 'cockscomb' habit.
Geological Context
Manganoan calcite typically forms in hydrothermal veins or manganese-rich sedimentary environments, often associated with other carbonate minerals and sulfides.
