From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
  
Cluster of sub euhedral striated prisms of Arsenopyrite with 4,3 x 3,6 x 2,5cm and 81 grams. Formed in mineralized veins of quartz, sulfides, wolframite, cassiterite, micas, fluorite, carbonates, among others, associated with the generation of a greisen dome by granitic intrusion in Paleozoic schists and graywackes.