I'm going to guess it's not stainless.. There are to many marks and gouges (heavy wear) for stainless.. Stainless is about as tough as is gets for jewelry (not counting tungsten)...
With wear like that, I would have to say silver or white gold.. If silver it would ring up at least around a silver quarter or even higher.. If white gold it could be anywhere between tab and penny... Stainless would be lower than the other two..
It looks to have been worn a lot, and the inside marks could have easily been worn away just the same, especially if its gold!
Cool save there, congrats!!!
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