A beautiful vintage ring. It's a spoon ring, but does not get very large (maybe made from a baby spoon?).
Marked inside the band "IS" which I believe stands for International Silver, they owned Rogers and several other silverware companies. There is wear to the metal, mostly on the back of the band. About a US size 5.5, but may be slightly adjustable due to it's wrap style.
I am always happy to answer any questions or send more photos when needed.