Have no idea what this is. It is made of some heavy metal but it's not rusty. Feels too hard to be brass, too light for lead, too clean to be iron. it was found about 3" deep in a park. It shows some pitting from corrosion but not rust. Thought it might be a wheel from an old toy but there's no center hub. It's 2-1/4" in diameter and about 3/8" thick. Anyone ever seen something like this?