Why this rock is probably not a meteorite:

Because it's another one of these things.
What is it?

This is some kind of sedimentary rock, a concretion of some kind. If a real geologist could enlighten me, I'd appreciate it.

Note added later: A viewer identified this as a cast of "goethite or related iron oxide," probably like #057


Prepared by:

Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you’ve found until you read this and this.