The 21-pound iron-nickel space rock was snatched from the school's Meteorite Museum during winter break.
The meteorite, which was a gift from a Soviet scientist during the Cold War, is valued between $20,000 and $40,000.
Authorities notified collectors around the world about the theft.
The thief had apparently sold the meteorite to a man in Missouri. Museum officials said they're just glad the thief didn't lose it.
Investigators were able to identify the thief because he used his real name during the transaction. The suspect has yet to be arrested.
The meteorite was once part of the asteroid belt between Mars and Jupiter and crashed in Siberia.
The Associated Press contributed to this report.