NOEL KING, HOST:
Good morning. I'm Noel King. Mona Sirbescu is a geology professor at Central Michigan University. People often bring her rocks and ask if they're meteorites. Usually her answer is no. But recently, a man came to her office with a 22-plus-pound rock just to check. Turns out it's the sixth-largest recorded meteorite found in Michigan, worth as much as $100,000. The man said that for 30 years, he'd been using it as a doorstop. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.