Rhodochrosite with quartz: Colorado, San Juan County, Silverton, Sunnyside Mine
The mineral specimen comes from the Sunnyside Mine, located near Silverton in the Eureka mining district (Silverton district), San Juan County, Colorado. The Sunnyside Mine, a major gold producer for the district, was located in 1873 and worked to the 1930s by the Sunnyside Mining and Milling Company. The Mine was closed after the 1930s, reopened and worked from 1959-1985, then worked by the Sunnyside Gold Corporation after 1985 to 1991. The Mine and associated American Tunnel are one of the best known sources of rhodochrosite in Colorado.