Very interesting ring! Personally I love it! Does it fit you--if so, I say wear it in good health--it is different and certainly a conversation piece. I am certainly no expert on antique rings--but as someone who inherited jewelry from some amazing and interesting ladies--I recommend looking to see if there are any marks on the inside of the ring that helps you to know the metal and recommend having the ring tested/taken to a jeweler if you have one you trust (which I didn't when I got most of my inherited things)--or getting a diamond and moissanite tester (which I did) to see if the stones are real to get a better idea of what it is.
The small coin looks like a Liberty Head coin, which would tend to suggest that the ring was made in the U.S. I was going to suggest that it's a replica since I couldn't see any ridges on the edge of the coin, but is it possible that the smooth edge is actually a frame holding the coin in place? Anyhow, I hope that helps...