Description

#1684 A 1.57 x 1.57 x 1.22 -inch specimen of white brassy Arsenopyrite crystals light tan Siderite from the Panasqueria Mine, Covilha, Castelo Branco, Portugal.  The arsenopyrite with siderite from the Panasqueira Mine formed in hydrothermal quartz veins within metamorphosed sedimentary rocks (schists and greywackes), related to a a deep-seated, late Variscan (Hercynian) granite intrusion. The mineralization is a classic example of a hypothermal W-Sn-Cu vein-type deposit.