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

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