Not sure at all

Is the object brass? A bit difficult to tell from the images, but are there two narrow slots, either side of the center oval that a leather strap may have been threaded through? Alternatively, does it appear to have two 'scars' on the back side where a "U-shaped" shank may have once been attached?

If so, one possibility is that it might be a bit of horse tack, horse rosette,
or harness/bridle decoration...

In any case, a very nice find! Congrats!
--Bert

I would guess it's a stamped metal brooch pin. Maybe held a stone in the center? Hard to tell. Cool find.