Verdigris: A green or bluish patina formed on copper, brass, or bronze surfaces exposed to the atmosphere for long periods of time.
The orange represents untarnished copper.
This was fun to work on, even though I had to put in quite a few hours. The silhouette took awhile because I'm not the skilled drawer that I once was in my youth, and I wanted to get correct (or close to) proportions. I am practicing drawing as I'd like to create some dancers in various poses.
I slightly altered the second photo so you can see the detail a little better.