- Chalcopyrite, Chalcocite
- Thumbnail, 2.3 x 1.4 x 1.3 cm
- 2100 Level, Campbell Mine, Ouray District (Uncompahgre District), Ouray Co., Colorado, USA
Here is a fabulous thumber for either a thumbnail collector or a Colorado collector: a very sharp TWIN of chalcopyrite with a coating of chalcocite which gives it its blue and gold iridescence. This is from the classic Ouray mining district, and is an old-timer and very hard to find now!