Rhodochrosite

Basic Knowledge

Rhodochrosite is a carbonate mineral with chemical composition MnCO3. It has a rose-red colour, its hardness varies between 3.5 and 4.5. It crystallizes in the trigonal system.

Its main use is as a source for manganese, but some jewelry is made from it, especially in Argentina. Some of most beatiful samples of this mineral come from the Sweet Home Mine in Alma, Colorado.

Rhodochrosite is faceted into cut stones for collectors. The banded stalactitic material from Catamarca, Argentina is carved into ornaments and polished into cabochons and beads for jewelry. Fine, blood-red Rhodochrosite specimens are highly desired by collectors, and command magnificent prices.

Rhodochrosite belongs to the calcite group, a group of related carbonates that are isomorphous with one another. They are similar in many physical properties. All members of the calcite group crystallize in the trigonal subdivision of the hexagonal system (as rhombohedrons and scalenohedrons), have perfect rhombohedral cleavage, and exhibit a strong double refraction in transparent rhombohedrons.

When rhodochrosite is exposed to the atmosphere, it develops a thin film of manganese oxide on its surface. This may slightly darken the color of a specimen. Rhodochrosite commonly alters into black manganese oxides, such as pyrolusite, manganite, and psilomelane.

Rhodochrosite most commonly forms in hydrothermal veins associated with silver, copper, and lead sulfides, but rarely occurs in pegmatites.

An interesting occurrence of this mineral is in Argentina, where rhodochrosite forms stalagmites and stalactites in 13th century Inca silver mines. The Colorado and South African rhodochrosite mines have produced specimens that many consider the most beautiful of all minerals. They occur in blood-red, transparent to translucent, perfectly shaped rhombohedral and scalenohedral crystals.

 

 

Bardic Knowledge

DC	Things Known
10 -Common
20-Uncommon
30-Obscure
40-Very Obscure

Rare Uses and Items

 

 

 

 

 

 

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