The Colorado Geological Survey asks, “Did you know that Colorado has a new state mineral?”

Title: The Colorado Geological Survey asks, “Did you know that Colorado has a new state mineral?”

Author: Vince Matthews

Publication: The Outcrop, June 2002, p. 17

Did you know that Governor Owens signed a bill on April 17, 2002, making rhodochrosite the state mineral? It won out over 773 other minerals found in Colorado and takes its place in history alongside the state gemstone, aquamarine (that’s blue beryl for those of you in Rio Linda). Colorado becomes the 20th state to have an official state mineral including gold (Alaska, California), coal (Kentucky), and galena (Missouri and Wisconsin). Senator Ken Chlouber and Representative Carl Miller sponsored the bill that accomplished this.

Rhodochrosite is a manganese carbonate, MnCO3. Iron can replace the manganese so that there may be a gradation in composition from ferroan rhodochrasite through manganoan siderite and finally to pure siderite, FeCO3. Rhodochrosite’s crystal habit is the rhombohedron typical of carbonate minerals. It is also found in Colorado as massive, dogtooth, disc-like, radiating, granular, stalactitic, and rosette forms. Although it is most commonly pink and opaque, Colorado’s translucent red variety is prized the world over, commonly bringing prices in the tens of thousands of dollars.

Rhodochrosite is found in eighteen of Colorado’s counties associated with gold, silver, lead, zinc, and molybdenum ores. Earth’s largest rhodochrosite crystal is on display at the Denver Museum of Nature and Science. This 6.5-inch crystal was collected in 1992 from the Sweet Home Mine in Park County. The Sweet Home Mine was claimed in 1872 and issued U.S. Patent #106, one of the earliest patents granted under the General Mining Law of 1872. This mineral that used to be discarded as waste on Sweet Home’s dumps has now brought it more fame as a rhodochrosite mine than it ever had as a silver mine.

To see some beautiful specimens of Colorado rhodochrosite and aquamarine, visit http:// geosurvey.state.co.us/ and click on “General Information”.

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