Almandine from Mineral Creek Bog Iron Deposit, San Juan County, Colorado, USA

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Semi lustrous sharp crystal of almandine measuring 3.7 cm in size embedded up on a schist matrix. In great condition. The specimen comes with a previous label from the collection of Ray DeMark.The Sedalia Mine in Chaffee County, Colorado, is hosted in Proterozoic metamorphic and volcanic terranes characterized by complexly deformed schist, gneiss, and amphibolite. Discovered in 1881 and extensively worked through the late 19th and early 20th centuries, it became a major producer of copper and zinc from massive sulfide lenses enclosed within the regional silicate rock formations. The site is particularly famous among mineral collectors for its remarkable metamorphic mineral assemblages, especially large, well-formed almandine garnet crystals that developed within the aluminous schists and garnetiferous units under intense regional thermal and dynamic metamorphism.