I found this a couple of days ago in a field next to an early 1800's farmhouse. It appears to be brass, and the right side is broken. Found it a couple of feet from a minie ball.
Then IMO as Spats ID'ed it being part of a spur, I say from the size a child's spur. With a screen name like Spats I'm sure he's the expert on footwear and apparel.