Pearceite-T2ac (also known as Arsenpolybasite) is a polytype of pearceite and is a rare silver, copper, arsenic, antimony sulfosalt. This fine and rich specimen from the Uchucchacua Mine features a 1.4 cm, mounded cluster of splendent, metallic-gray arsenpolybasite crystals jauntily perched on a sliver of quartz on a sculptural matrix of sulfides, which includes scintillating vein of arsenpolybasite crystals. Ex. David Ellis Collection.