Well-formed arsenopyrite crystals occur included into sericite talc schists, associated with pyrite. The arsenopyrite, commonly twinned after (101) and (110) , shows the following crystallographic forms: (110) , (014 ) and more rarely (001) and (011) . The arsenopyrite is frequently fractured, exhibiting inclusions of euhedral pyrite crystals, which probably have been formed through replacement by penetration of forming solutions into the arsenopyrite small cracks