No idea what this one could be.
It was covered in red rust when I found it, so I left it marinating in sulfuric acid for the night. Before, it looked almost golden under the crust, but now it's clearly metallic grey.
It's also very dense and heavy, more so than iron by my rough estimate. Also, it's non-magnetic.

Maybe a more educated anon would know more. I'm completely clueless about geology.