Silver ring

Beautiful ring! This ring is a size 8/8 1/2 It is silver coated,it looks like it's made out of copper/brass? I'm just not sure, haven't ever seen a ring like this before.It is adjustable but,good luck with that,I tried to adjust it and it was a no go.The inside is very strange looking, haven't ever seen that before either,it is heavy. There are a couple of small nicks in the bottom of the stone as shown in the picture. Still a beautiful piece!