Dolomite with Calcite, Quartz

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Rich chocolate brown rhombohedral crystals of dolomite on matrix with calcite and minor quartz. This is in very good condition.Shaft 371, located near Hartenstein in the Saxony region of Germany, was a major deep-extraction uranium mine operated by the Soviet-German SDAG Wismut company. Sinking of the shaft began on April 4, 1956, and it was officially commissioned on May 2, 1959, remaining active until operations ceased on March 1, 1991. Geologically, the shaft provided access to the rich Niederschlema-Alberoda deposit system, which is part of the massive hydrothermal vein mineralization hosted within the metamorphic and igneous complex of the Western Ore Mountains. Descending more than 1,800 meters deep, it targeted complex multi-stage vein structures containing pitchblende alongside carbonate and quartz gangue, making it one of the most productive and deepest uranium operations in Europe.