A fine and uncommon specimen of pyrite crystal with a partial chalcocite coating from the famous Milpillas Mine, Mexico. The pyrite has a perfect and sharp shape with beveled corners. Some faces are black due to chalcocite coating. Brassy yellow faces are seen too. Complete all over. For references see the 2021 issue of The Mineralogical Record vol. 52, # 5. In excellent condition. On acrylic base.

Killer!