Photo #155
https://ball-pythons.net/forums/cach...ked_jiajw0.jpg
Bornite is a copper iron sulfide ore, it looks gold when freshly exposed, and tarnishes into iridescent colors giving it the common name 'Peacock Ore'.
The amount of copper and iron can vary significantly in each piece, this particular piece was heavy on copper sulfide which made it problematic to polish.