A Chalcopyrite twin crystal sits perched on Pyrite with accents of Quartz and (maybe?) Ankerite, though the Ankerite could be just a ferroan Dolomite and has not yet been tested in a lab. The high luster of the modified Pyrite crystals juxtaposes the patinaed Chalcopyrite crystal. Similar to Cornish examples, a few nicks in the superficial oxidation coating reveal the metallic golden color below. A truly showy example of sulfide minerals from Zacatecas.