Golden crystals of chalcopyrite to 0.8 cm in size across the top of a dolomite crystal matrix. Some damage present as seen.The Dreislar Mine in North Rhine-Westphalia, Germany, began operations as an iron and copper prospect documented as early as 1777, transitioned into intensive commercial baryte extraction during the 20th century under various owners including IG Farben and Sachtleben, and finally ceased production around 2007 to 2008. Geologically, the deposit consists of steep epigenetic hydrothermal baryte veins cutting through Lower Carboniferous clay slates and greywackes of the Rhenish Massif. These mineralized structures formed as hydrothermal fluids filled a major fracture system related to regional tectonic activity, creating a prominent vein network that made Dreislar one of Germany's most important industrial baryte producers.
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