Sphalerite with Dolomite

Unknown Owner

Translucent lustrous orange red crystals of sphalerite nice on matrix. In very good condition.The Las Manforas Mine, situated in the Aliva mining district within the Picos de Europa mountains of Cantabria, Spain, is world-famous for producing the highest quality gem-grade sphalerite. Geologically, the deposit is a Mississippi Valley Type (MVT) zinc-lead occurrence hosted in Carboniferous limestone and dolomite. The mineralization resulted from relatively low-temperature hydrothermal fluids that replaced the carbonate host rock, forming large pockets filled with exceptionally transparent, honey-yellow to intense orange-red sphalerite crystals. Historically, while mining in the Picos de Europa dates back to the 19th century, the Las Manforas site saw its most significant industrial activity from the mid-1940s until its closure in 1989. Operated largely by the Real Compania Asturiana de Minas, the mine was primarily a source of zinc ore, but it became a legend in the mineralogical community for the spectacular, translucent "ruby jack" specimens discovered in its lower levels. Today, the mine is part of a national park, and its specimens remain the global benchmark for transparency and color in the species.