Rhombohedral Rhodochrosite Crystal

Rhodochrosite
Manganese Carbonate, MnCO3
Crystal System: Hexagonal
Hardness: 3.5-4.5
Density: 3.3-3.6

Rhodochrosite is a member of the calcite group. It occurs as a common gangue mineral in sufide mineral deposits and hydrothermal veins containing ores of copper, lead and silver. It is formed under a wide range of temperatures. Rhodochrosite also occurs as a secondary mineral in iron and manganese oxide deposits. It is also associated with metamorphic and metasomatic rocks of sedimentary origin.

Rhodochrosite most commonly occurs as granular, mammillated, concretionary, reniform and stalactic masses. More rarely it is found as rhombohedral crystals which vary from brown to light grey to translucent pink crystals with a vitreous to pearly luster. When exposed to air, rhodochrosite can become covered with a dark film of manganese oxide.

David Michaels provided the following on this specimen:
"The Rhodochrosite is a rhomb from Silverton, Colorado. This area has gotten less hype than Alma, and while the stuff isn't quite as gemmy, it is sweet (pardon the pun!)."


Rocks from David Michaels' Collection

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bkeller@rockhounds.com 11/5/95