The iridescent colours are on the surface, as a tarnish. They include green, yellow, blue, reddish-purple ... The mineral is opaque.
Peacock ore has several other names, Bornite, Erubescite and Variegated copper ore. Peacock Ore is an old miner's term, and it seems the best description. "Iridescent" means "like a rainbow", and that's quite a good description as well. It seems rather a frivolous stone, but it's an important copper ore.
Larger pictures of Peacock Ore:
These three natural specimens show the sparkle of the metallic coating.
This photo of the same three specimens give an idea of the colour range.
