I'm not too familiar with metals and what not, so I couldn't say what it's made of. It seems fairly tarnished, so perhaps it is brass or bronze. As for markings on the back, there are none. There is a real tiny hole on the back that is off-center and isn't very deep. Kind of looks like a mite was eatin away at it (just an analogy), since it isn't a perfect hole and is real tiny.
Me and my parents were cleaning out a house and we were told we could take whatever we wanted that was being set for trash. Ended up getting a lot of antique stuff including china sets, diner table set, even an old china cupboard, etc. Then there are things like these that we have no clue what they are. The ring is very small and doesn't fit over the first knuckle on my pinky finger. So I don't know if it could of been used as a slide. The bended pieces were binded to a half ring to form a whole ring. So the bended pieces are actually shorter than you are thinking KC. I'm assuming it was a gift to a child. The owner of the house was elderly (80's+) so perhaps it was passed down from a father or used as a memory keepsake. It just looked like an old stamp seal used to seal envelopes shut, but that was just my first impression. I will agree that it is military and the uniform hat pin seems a likely approach. It's just hard to say.
That's all I know about it. I thank all of you for getting this far, I appreciate it. And any more insight is still welcomed. Thank you again.