Hi! I picked this blackish rock(?) in a sunflower field in central South Dakota. I also picked up 1 other black rock (2 total) specimen(s) on this same field which I will post in a separate post. It is heavy for its size and has a crusty grainy texture to it. Not magnetic (dang!). I can attempt more pictures if requested — the light wasn’t great here today. Anyway I hope someone out there might be able to help identify this!