Patina Experiments on Mixed Silver Clay and Electroformed Copper

I'm continuing with my experiments on electroforming copper onto silver clay. Today I finished a pair of hoop earrings, complete with the high contrast patina. After finishing them, I decided that I wanted to polish the silver more and then patina again. Although the copper is very tough and suffers motorized polishing beautifully, the patina after mechanical work is different.

So, chemistry experiments are in order. Right up my alley.