A 12-pound meteorite from the moon was sold at a Boston auction for the out-of-this-world price of $612,500 on Friday.

“As soon as we saw this, we knew it was extraordinarily unusual,” Geoff Notkin, star of television’s “Meteorite Men,” said. “This is close to a once-in-a-lifetime find.”

Most lunar meteorites found are the size of a walnut or golf ball, said Notkin, who is CEO of Aerolite Meteorites, which sold the rock.

Boston-based RR Auction announced the winning bid on Friday to a representative working with the Tam Chuc Pagoda complex in Ha Nam Province, Vietnam.

RR said it’s one of the biggest pieces of the moon ever put up for sale in the online auction that ran from Oct. 11 until Oct. 18.

The lunar rock was found last year in a remote area of Mauritania in northwest Africa but probably plunged to Earth thousands of years ago.

The lunar meteorite is unofficially called “The Moon Puzzle,” Geek Wire reported, as it is composed of six fragments that fit together like a puzzle. The largest of those pieces weighs about 6 pounds.

“…this ‘Moon Puzzle’ will certainly inspire students of science for generations to come,” Robert Livingston, RR’s executive vice president, said, according to the publication.

It is also one of the few known lunar meteorites with what experts call “partial fusion crust,” caused by the tremendous heat that sears the rock as it descends through the atmosphere.

“It actually toasted on the outside,” Notkin said.

Livingston said the moon rocks brought back by astronauts are U.S. government property, so the auction was the only way a private collector could obtain on a piece of the moon.

The Associated Press contributed to this report.