Calcite with Quartz, Sphalerite, Siderite

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Attractive combination piece with crystal groupings of calcite to almost 3.0 cm in diameter on a grouping of crystallized quartz with siderite and sphalerite. In good condition. This is crystallized completely all around. The Herja mine, located near Chiuzbaia in the Maramures region of northern Romania, is situated within the Neogene Baia Mare metallogenic district. Geologically, the ore deposit formed during the Late Miocene to Pannonian epochs as hydrothermal vein systems associated with subvolcanic intrusions, particularly porphyry quartz-microdiorite stocks and surrounding andesites. These mineralized veins, numbering over 260 across a compact network, contain extensive base-metal concentrations of lead and zinc, along with silver, antimony, and gold. Historically, mining in the region dates back to the Middle Ages, with formal operations continuing under Hungarian and Habsburg administrations to extract industrial metals. While the mine was worked for centuries for its rich ores, it became renowned among mineralogists for producing highly diverse sulfide and sulfosalt specimens, including stibnite, berthierite, and unique dark calcite. The underground workings were permanently closed in 2005, ending centuries of active extraction.