Calcite with Barite, Fluorite

specimen number:
2013103

location:
Annabel Lee Mine, Hardin Co., Illinois, USA

description:

A very fine large combination piece for this locality with gemmy scalenohedral crystals of calcite and groupings to 3.2 cm in size across the top of a purple cubic fluorite crystal matrix. Colorless crystals of barite to 1.0 cm in size are scattered throughout. This was collected in the mid 1980s. In very good condition.

The Annabel Lee mine, situated near Harris Creek within the famous Cave-in-Rock District of Hardin County, Illinois, is an outstanding American mineral locality celebrated for producing some of the world's finest, most intensely colored fluorite specimens. Geologically, this prolific deposit is an exceptional example of a Mississippi Valley-Type (MVT) mineralization system, where low-temperature, metal-bearing hydrothermal fluids ascended along the regional fault zones of the Illinois-Kentucky Fluorspar District. Mineralization occurred primarily as bedded replacement bodies and open-space cavity fillings within Mississippian-age sedimentary rocks, specifically the Joppa and Downeys Bluff members of the Ste. Genevieve and Renault Limestones, where fluorite precipitated as magnificent, sharp cubic crystal clusters displaying incredible multi-colored phantom zoning in shades of deep purple, golden yellow, amber, and clear blue, often accompanied by well-crystallized barite, sphalerite, and calcite. Historically, the Annabel Lee mine was a late and highly significant addition to the district, discovered via deep exploratory drilling and developed as a modern underground trackless mining operation by the Ozark-Mahoning Company, with the sinking of its main shaft commencing in 1982. The mine entered full production in 1984 and operated with exceptional intensity as a premier supplier of metallurgical and acid-grade fluorspar until changing global markets, cheap foreign competition, and localized reserve depletion forced the permanent cessation of all underground mining operations and the capping of the shaft in 1995, marking the end of the grand era of major Illinois fluorspar extraction.

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