Background of the Elmwood Mine
The Elmwood mine, nestled in the small central Tennessee town of Carthage, has been in operation since 1975, producing and processing hundreds of thousands of tons of zinc.
Zinc was first discovered at the location of the mine in 1969 by the Jersey Minièr Zinc Co. After opening in 1975, the mine operated until the closure of the mine owner in 2004. Shortly after its inception, the Elmwood Mine gained a reputation for producing a variety of fine minerals, including large crystals of Calcite and Fluorite, as well as ivory-white spheres of Barite and jet-black Sphalerite. The mine was reopened in 2010 under the operation of Belgian mining corporation Nyrstar. Since then, Elmwood classics have returned to the market, with specimens making their way to private collections, museums, and gem show displays alike.
Mineralogy of Elmwood
A multitude of metallic oxide, halide, and carbonate minerals are found in the carbonate rocks of the Carthage region. The four signature species of Elmwood mine are Fluorite, Sphalerite, Barite, and Calcite.
Barite
Barite commonly occurs as bone-white spheres at the locality. The size of these spheres are variable, ranging from about an inch across to nearly a foot wide. The formation of Barite is unique to the Elmwood Mine, and no known similar spherical aggregates exist worldwide.
Calcite
The calcite found at Elmwood Mine is among the most famous in the world, attaining notability for the sheer size of its dogtooth crystals. Specimens of calcite often take a golden brown hue marked by translucence, but milky white crystals have also been found. The largest crystals measure over one foot long.
Fluorite
Crystals of Fluorite characterized by a purple hue and stepped faces are present at the mine. Elongated "Carthage Corner" Fluorites have also been recovered from the site. Specimens of Fluorite are often associated with Barite or Sphalerite. Some crystals exhibit dark points, likely due to an overgrowth of Fluorite which encapsulated another mineral, such as Marcasite.
Sphalerite
Sphalerite, the primary ore of zinc, found at the Elmwood Mine occurs in lustrous, jet-black colored crystalline masses. Many crystals have complete or partial terminations.
Minor Minerals
Other minor Elmwood minerals include:
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Quartz
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Metal Ores
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Galena - Lead Ore
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Marcasite - Iron Sulfide
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Bitumen - Petroleum (Liquid or partially Solid form)
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Dolomite - Carbonate Mineral
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Celestite
References
Gaylord, W. B. (1996). Geology of the Elmwood AND Gordonsville Mines, Central Tennessee Zinc District- An Update. In K. C. Misra (Author), Carbonate-Hosted Lead-Zinc-Fluorite-Barite Deposits of North America. Littleton, CO: Society of Economic Geologists.
"Elmwood Mine, Carthage, Smith Co., Tennessee, USA", Mindat, Mindat.org ↗, 17 August 2020 https://www.mindat.org/loc-4125.html ↗