From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
 
 
Cluster of smal prismatic crystals of Arsenopyrite with aprox. 1,5-2,0cm. Formed in mineralised 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.