Calcite, var. Manganoan

This specimen is a classic example of manganoan calcite from the Idarado Mine in the San Juan Mountains of Colorado. It features lustrous, pastel-pink, translucent scalenohedral crystals with frosted faces, free of matrix. One crystal shows minor cleavage, but the rest remain intact, making this an excellent display specimen. Under UV light, the calcite exhibits a striking neon orange-pink fluorescence.

The Idarado Mine, named after the Idaho-based Sunshine Mining Company and Newmont Mining in Colorado (IDA-ho + colo-RADO = Idarado), was a major Pb-Cu-Zn producer. Located approximately 10 km south of Ouray, the mine extended into the Red Mountain District and near Telluride in San Miguel County. The deposit, consisting of Tertiary telluride conglomerate, was mined until its closure in 1978.