Black Patina for Silver

I've become quite take with super black patina for silver, such as seen in the jewelry of Allyson Bone:


or Natasha Wozniak:


or Jayne Redmond, among others:


So, I decided to try to get a deep dark black on the front piece for my stilt rivet brooch. I'm going to polish off highlights on the branches, I think, as I love the idea of reversing contrast between the bright white of the faux bone with black behind black with silver highlights on top. That brings back memories of quilting, where reversing values at a border was a favorite technique for me.

Next step: stilts/tubes/offsets of some kind with rivets.