The pink color of rhodochrosite is caused by the element manganese and it is formed when manganese is dissolved by ground water and combines with a carbonate material and then drips off the ceiling of caves and crevices deep underground. It is found in Argentina, Peru, Colorado and Montana, U.S, and Quebec, Canada.
It is commonly found in the form of stalactites and stalagmites in the caves of Argentina. Rhodochrosite (whose name means rose-colored) often forms pink and white bands. It is often carved into figurines or boxes while the tubular stalactite formations are often sliced for use in jewelry. Fine gem quality crystals are sometimes cut into gemstones for use in high end jewelry, but the more common grade is used extensively in silver and gold jewelry.
Rhodonite, another pinkish stone, is often confused with rhodochrosite because the base color is similar, but most rhodonite used for jewelry purposes contains black manganese oxides while rhodochrosite is banded with white.
Rhodochrosite became the official state mineral for Colorado in 2002 after the Platte Canyon High School in Bailey,Colorado made the proposal based on the fact that the Sweet Home Mine near Alma, Colorado produces the highly prized and rare red crystals which are found only in a few places on earth.
Rhodochrosite is a relatively soft stone and ranges between 3.5 and 4.0 on the Mohs scale of hardness.