Arsenopyrite with Fluorapatite

specimen number:
9273007

location:
Panasqueira Mines, Castelo Branco, Portugal

description:

Beautiful blue iridescent crystals of arsenopyrite in a cluster with minor fluorapatite. In great condition, the luster and color makes this piece very attractive. Siderite are scattered throughout.

The Panasqueira mines, situated within the Castelo Branco district of central Portugal, represent one of the world's largest, most historically significant underground tungsten, tin, and copper mining operations, universally celebrated for producing mineral specimens of ferberite, cassiterite, and chalcopyrite alongside crystals of fluorapatite that are usually green and sometimes purple in color. Geologically, this deposit is a classic example of a post-tectonic hydrothermal vein field, where the intrusion of the Late Hercynian Panasqueira granite pluton beneath a thick sequence of Cambrian-age metasedimentary schists and graywackes drove intense fracturing and fluid migration. This extensive process generated a vast, sub-horizontal network of quartz-dominated structural veins rich in ferberite, which are studied by international mineralogists for their razor-sharp crystals often associated with pyrite, arsenopyrite, and large carbonate rhombohedrons. Historically, formal commercial exploitation began in 1896 following the initial discovery of tungsten mineralization by local prospectors, leading to the establishment of the Wolfram Mining and Smelting Company in 1911 and centuries of corporate evolution under Beralt Tin and Wolfram Limited, which developed underground tunneling to supply strategic metals during World War I and World War II. Through 2026, despite experiencing intermittent temporary shutdowns over the decades due to global metal price volatility, the complex continues active commercial underground extraction under Almonty Industries, maintaining its position as a primary European industrial producer of tungsten concentrates and a geological benchmark for studying granite-related hydrothermal vein systems.

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