Not sure what this is, button cover maybe?

[AnonymousTurker]

imgur: the simple image sharer I'm posting the imgur link so you can more easily enlarge it to see details. It's thin but heavy for it's size.

 

[Mud Hut]

Those photos are way to small for my tired eyes

 

[G.I.B.]

Nothing to compare the size with either. It also helps to know about where in the country (or what country) it was found in.

What type of metal?

You need to provide some details, can't help without more information.