Three tiny Moon rocks brought back from space by the Soviet Luna-16 mission are expected to sell for up to $1 million when they go up for auction later this week.

Cassandra Hatton, vice president and senior specialist for books and manuscripts at auction house Sotheby’s told Fox News that the sale is extremely unusual. “You cannot buy or sell lunar material unless you have documentation proving that it can be owned by a private individual,” she said. “As far as we know, this is the only lunar material that actually has that documentation, so it’s the only lunar sample that can be legally bought by a private individual.”

BAG OF NASA MOON DUST SELLS FOR $1.8M AT AUCTION

Retrieved from the lunar surface in 1970, the samples were presented to Nina Ivanova Koroleva, widow of Sergei Pavlovich Korolev, the former director of the Soviet space program. The rocks were sold by Sotheby’s to an anonymous American collector for $442,500 by in 1993 and remain in that person’s collection.

The rocks have a pre-sale estimate of $700,000 to $1 million and the lot will be auctioned on Nov. 29.

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There is great interest in Moon-related artifacts. Last year, for example, a bag filled with Moon dust by Apollo 11 astronaut Neil Armstrong was sold by Sotheby’s for $1.8 million.

The bag had previously been misidentified and mistakenly sold at an online government auction for $995. The Chicago-area woman who purchased the bag won an intense court battle with NASA, which attempted to retrieve the artifact.

The Associated Press contributed to this article.

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