I used to have one of these just like this but somehow lost it or was stolen. Anyway I never would have imagined I would see another one let alone have the chance to buy one. Sorry I just have to share this with someone and Coin Talk is by far the best place for me to share. I will tell the whole story about it after someone here can guess what it is. Ill give you a few clues, it is not a coin, and if you have read any of my posts talking about where I lived before and found a lot of my ancient coins it might help. So please make your guesses !
Bcuda, it looks like an upside down grenadier badge. Not the type that would go on a hat but the kind that was sewn on to coat tails to keep them folded back.
You are close enough yes it is upside down and it looks a grenadiers pin. It is an Artillery (Exploding cannon ball) type applique that has two very crude square sided nails on the back that would have been applied on some kind of wood. And if they had grenades in the 1600s then possibly perhaps a crate of cannonballs or grenades ? I am not sure. It is very very thick so as not to bend when hammered into some wood. Now for the story I had one exactly like this one that I had found in Spain and this one that I bought is also from Spain. It is basically the same exact one I had that I found metal detecting. Some times during the winter time in Spain and when a big Northern storm would come in there was a beach I would go metal detect the very next day and I would find loads and loads of Spanish 8 maravedis coins from the early 1600s from a Spanish ship wreck that was close by that has washed up from the storm. My friend and I would get up early and hit that beach and come home with all kinds of stuff. I had found one of these just like in the pic above at that same site and somehow lost it. My friend found a flint lock what we called a blunder buster gun with some of the wood still intact (had barnacles growing all over it) there also. This area we would metal detect had some large naval battles with the Spanish and English and was rich in artifacts. I just never thought I would ever see one again. Am pretty excited to have a second one.
Certainly looks like a grenadiers badge. I have a current one turned upside down; sorry no pic to send.
...uh..ole Hispanicus knew it...and i'll give @Robert Ransom the title of most prolific guesser award...