This beautifully crystallized piece, formerly in the noted collection of Stig Adolfsson then went to the Bergskolan Filipstad, Sweden. Bergskolan is swedish for school of mining. Filipstad is a small city in the south of Langban with this famous school of mining. It is a fairly rare copper cobalt sulfarsenide. It features a mirror-bright luster, and a battleship gray color along with modified faces. It is complete all around, though with very minor edge wear here and there. Given the significance, I can live with that and consider any small wear trivial in context. Crystals of this size are considered HUGE for the species, and I have never seen such a large example for sale before and this is a museum quality rarity