Looks like an Archangel amulet to me. Carried for protection. Difficult to date, and they're still being made today as repros although most usually in pendant form with a suspension hole:
Because yours is not holed, it would seem to be the world war 1 medal which attached from a small rim loop. Yours may show remnants of the spotweld.....and btw, I would not get too excited at the eBay ASKING. Price.