Thursday, October 20, 2011

Rhodochrosite - A Common But Unusual Gemstone !

Rhodochrosite (whose name means rose-colored) is a very attractive mineral with an absolutely one-of-a-kind, beautiful color. Although it can be an ore of manganese, it is its ornamental and display specimen qualities that make it a very popular mineral. The color of a single crystal can just astound the observer with its vivid pink-rose color that seems to be transmitted out of the crystal as if lit from within. Individual crystals are found in well shape rhombohedrons and and sometime in rarer scalahedrons. In a massive form its pink and white bands are extremely attractive and are often used in semi-precious jewelry. Rhodochrosite is often carved into figurines and tubular stalactitic forms are sliced into circles with concentric bands that are truly unique in the mineral kingdom. Fine crystals are sometimes cut into gemstones, but Rhodochrosite's softness and brittleness limit it as a gemstone for everyday use. Identification of Rhodochrosite is fairly easy despite a few similarly colored minerals such as Rhodonire. Rhodonite is harder and has different cleavage; but perhaps the best distinguishing factor is its lack of reaction to acids. Rhodochrosite will easily with show some reaction to cold acids which demonstrates its carbonate chemistry. Basically, any rose-pink carbonate is considered Rhodochrosite; however some Calcites with a small amount of manganese impurities can be pink in color. The manganese replaces some of the calciums in calcite but a complete series between Calcite and Rhodochrosite is not established. There are many localities for Rhodochrosite that are of great reknown. Beyond a doubt, the best locality for Rhodochrosite is the Sweet Home Mine in Colorado. It is unmatched for its superb Rhodochrosite crystals that exhibit the best features of the species; a fine bright rose color and sharp well formed crystals. Some specimens from here are quite large and of world class distinction. Other localities have produced some fine specimens as well. Catamarca, Argentina has an old inca silver mine that has produced fine stalatitic examples of Rhodochrosite that are unique and very attractive. Cut cross-sections reveal concentric bands of light and dark rose colored layers. These specimens are carved and used for many ornamental purposes.

A whole table of Rhodocrosite at a Gem Show, however just one small specimum from the Sweet Home Mine in Colorado. Most of the specimums were from Argentina.