From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
  
Cluster of striated sub euhedral prisms of Arsenopyrite with 3,5 x 3,4 x 2,5cm and 77 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.