Sphalerite from Elmwood Mine, Tennessee, USA

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Superb lustrous crystal groupings of sphalerite measuring to 4.7 cm in size across the top of a crystallized quartz matrix with dolomite and fluorite. This is in super condition. The Elmwood Mine, located in Smith County, Tennessee, is globally famous for producing some of the worlds finest crystallized sphalerite specimens. Geologically, the deposit is a Mississippi Valley Type (MVT) occurrence hosted within the Ordovician-aged Knox Group carbonates, where dissolution of limestone and dolomite created large brecciated cavities and vugs. These open spaces allowed for the growth of spectacular, lustrous, and complexly twinned sphalerite crystals, which are frequently associated with transparent golden fluorite, snowy white barite, and sharp calcite crystals. Historically, the mine was opened in 1969 by the New Jersey Zinc Company and began large-scale commercial production in the early 1970s, primarily for zinc ore. The operation has experienced several periods of closure and reopening due to fluctuating metal prices, notably shutting down in 2004 before being acquired and restarted by Nyrstar in 2010. While the mine remains a major industrial producer of zinc, it is cherished by the mineralogical community for the unique "ruby jack" and dark, multi-faceted sphalerite crystals that have become iconic staples of American mineral collecting.