Why this rock is probably not a meteorite:

This one came from near Tucson. It registered on a metal detector. Up close, many of the the "clasts" (which are really phenocrysts) are rectangular. That's a sure sign that the rock is not a meteorite.
What is it?

Another porphyritic volcanic rock. Such rocks are common in the mountains of southeast Arizona. It probably contains a smidge of magnetite.


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.