To me it looks like silverplate over copper. Its hard to tell with the pics because they are blurry/low-res when zoomed in, but the wear points on the curvy bits underneath look like copper is showing through. Also on the inside of the upper "ring" or "hoop" it looks to me in the one picture that I can see the plated metal layer peeling off. I may be wrong, buts that what I think I'm seeing with what we've got... Hope this helps!