Chalcanthite is a water soluble, copper sulfate found on or near copper. Since it dissolves easily, it is generally found in arid regions, and less frequently occurs in wetter areas. It is used in some holistic health applications and as a teaching tool in schools because of its ability to crystallize quickly. On a few occasions, the mineral is found in such abundance that it can be mined for copper ore.
Chalcanthite has a long list of synonyms. The word derives from the Greek and means 'copper flower'. One can find it called blue vitriol, cyanose, cyanosite, copper vitriol, or calcantite. It has 20 synonyms or varied names in different languages, in all.
Chalcanthite is formed when copper is oxidized, usually after copper has been mined. It grows on the walls of mines. It ranges in color from green to the more common blue. Chalcanthite crystals are transparent or translucent, but soft, having a hardness on the Moh's scale of only 2.5. It breaks easily and has a sharp, brittle texture.
Though lovely in appearance, it's hard to keep chalcanthite as a collector because over time accumulated moisture will dissolve it. Museums that showcase it usually end up losing their samples at some later date due to chalcanthite's solubility. Also, amateur rock hounds should not perform a taste test on the mineral because it is extremely poisonous. As a poison, chalcanthite was formerly used to clear ponds of excessive plant growth. It is no longer used because of its possible negative impact on the environment.
With due caution, chalcanthite is an excellent tool for teaching children about crystallization. Its color and the ease at which it forms into crystals impress many. However, care must be taken to keep these attractive crystals, reminiscent of candy, out of children's reach because ingestion of them can lead to serious or fatal consequences.
Despite its toxicity, chalcanthite is used by holistic medical practitioners as an oral medicine to purge the body of toxins and phlegm. It is also used externally to reduce abscesses and dead tissue, and to reduce inflammation of the skin. It should never be used either internally or externally without the guidance of a physician, and also should never be used by pregnant women or young children.
Chalcanthite is readily available on the Internet and in rock shops. Powdered forms for both science experiments and health purposes are inexpensive. Though it is not the most useful of minerals, by far, it is certainly prized as one of the best looking. Finding chalcanthite in its natural setting is quite a coup to rock collectors, who enjoy its lustrous but transient nature.