Once again, I agree with Creskol. Because you didn't know what it is, I'm just replying to add that your mid-1800s "camping style" iron candleholder originally had an approximately 2"-long square-bodied nail projecting down from its base. (The nail rusted off or broke off of yours.) The nail allowed you to stick the candleholder into an old log, or even just into the ground, for stability. Being lightweight and small, it seems to have been a popular item with civil war soldiers, because many have been found in civil war campsites.