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Occurrence of Turquoise Group Minerals in the Eastern United States
Henry Barwood
Indiana Geological Survey
611 N. Walnut Grove
Bloomington, Indiana 47405
Most collectors associate turquoise group minerals with the Western United States, where large and rich deposits of gem-grade material have been mined for centuries. Mineral collectors are generally aware of the turquoise crystal locality near Lynch Station, Virginia, but seldom know about other eastern U.S. sites where turquoise, planerite and coeruleolactite have been found. Turquoise group minerals have been found abundantly in Pennsylvania, Virginia, Georgia, Alabama and Arkansas.
In Arkansas turquoise and planerite are found in the Arkansas Novaculite (with iron phosphates) and in the Bigfork Chert (with aluminum phosphates). Massive turquoise was mined from novaculite at Porter Ridge (also known as the Mona Lisa or McBride mine) in Polk County during the 1980's. Production figures are not available, but "many tons" of both hard and chalky turquoise were produced. The turquoise was processed and sold for lapidary use. Thin veins of planerite are common on Buckeye Mountain in Polk County and other iron phosphate localities as well as the type section of the Novaculite at Caddo Gap. At the Coon Creek mine in Polk County, rare, tiny green crystals of a mineral, originally identified as "rashleighite," but now believed to be more like planerite, are found. Planerite occurs with wavellite and variscite...