A particularly beautiful specimen showing intense colors due to oxidation of the chalcopyrite, with crystals to about 1 cm on matrix. A note: Some people I do trust swear to me that these are found in the mine, already colored - and others are suspicious that the colors intensify if cleaned with chemicals. I can tell you only that some DO occur naturally in the mine, and the color is seemingly the result of the crystals interacting with running water in a natural environment. It is probably not possible to tell if the color has been amplified by cleaning chemicals, which might further oxidize the copper in the chalcopyrite to give more color. ex Richard Rossi collection.