Description: This mineral specimen which shimmering with colorful metallic luster, looks like a pile of metal coins, from Daye, Hubei, China, wide around 10cm. We analyzed it and found that the specimen is composed of many sheet-like Calcite which surface be covered by a layer of Pyrite. Due to the thin oxide layer on the surface of Pyrite, the light interferes with the thin film, resulting in such a rich and colorful color! A very beautiful mineral specimen!