Originally labeled as Sternbergite and but confirmed visually as the dimorph Argentopyrite by Mark Feinglos. It is his favorite mineral and he was astonished by the the number of Argentpyrite crystals on this specimen.
The specimen is mostly Pyrargyrite but is full of micro 1mm and less bronze to metallic gray Argentopyrite crystals. The photos do not do it justice. The crystals are orthorhombic twinned pseudohexagonal prisms with prominent re-entry angles appearing as deep striations. It's the same twinning involved in the Aragonite crystals also in this update.