Looks like old photo frame that had a rotating center with a photo on front and back? Or maybe I'm just crazy and it's a fancy electrical socket plate?
I don’t see why it wouldn’t be an item worn as a brooch, if the loops suggest it once had a vertical pin rather than some kind of strut that allowed it to be free-standing. I would say its very typically late Victorian and possibly a ‘mourning brooch’ which might have held a picture of a loved one or a lock of their hair.
I didn’t recall ever having seen a rectangular one (they’re usually oval or round), but a quick Google shows they did exist. This one has a ‘tintype’ portrait of a deceased loved one in it:
I can’t see if the loop arrangement at the back is consistent with a central portion that rotated, but those certainly existed too. Like this:
The two sides usually had a combination of portrait and lock of hair, but other combinations also existed including monograms, pressed flowers etc, and sometimes two parents or even two children (early death was sadly quite common). They weren’t designed to rotate when you were wearing them… you chose one side or the other.
At the bottom right of the back of your piece, are these maker’s marks on the bottom rim or just flaws in the metal?
At 1.65 inches wide and 2.24 inches tall I would have to go with the picture frame or brooch ID. But, being that small it might also be a sash buckle and the pin or tongue is missing.
