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Three tiny moon rocks, collected by a Soviet space mission in 1970, are expected to sell for up to $1 million when they go to auction in November.

Sotheby’s says the minuscule fragments, valued between $700,000 and $1 million, are the only known and documented lunar rocks to be available for private ownership.

Two abandoned Soviet space shuttles left in the Kazakh steppe

The two largest pieces measure just two by two millimeters – about as thick as the side of a nickel coin – while the smallest piece is just one by one millimeter, smaller than some grains of sand.

They were retrieved by the unmanned Luna-16 Mission in 1970, and were first sold in 1993 by the widow of former Soviet space program director Sergei Pavlovich Korolev.

Since then, the rocks have been in the hands of an unnamed American individual, who has now put them up for sale.

Two handwritten notes penned by Albert Einstein have been sold at auction for a combined $1.8 million.
Two handwritten notes penned by Albert Einstein have been sold at auction for a combined $1.8 million.
MENAHEM KAHANA/AFP/AFP/Getty Images
The notes written in German, which the famed physicist gave to a Tokyo courier in November 1922 in lieu of a tip, contain two aphorisms for happiness.
The notes written in German, which the famed physicist gave to a Tokyo courier in November 1922 in lieu of a tip, contain two aphorisms for happiness.
MENAHEM KAHANA/AFP/AFP/Getty Images
The notes are written on notepaper from the Imperial Hotel in Ginza, Tokyo, where Einstein was delivering a series of lectures. Scroll through the gallery for other fascinating objects to go on auction.
The notes are written on notepaper from the Imperial Hotel in Ginza, Tokyo, where Einstein was delivering a series of lectures. Scroll through the gallery for other fascinating objects to go on auction.
MENAHEM KAHANA/AFP/AFP/Getty Images
In May, Christie's listed a series of rare meteorites as part of its "Deep Impact: Martian, Lunar and Other Rare Meteorites" annual auction of extraterrestrial specimens.
In May, Christie's listed a series of rare meteorites as part of its "Deep Impact: Martian, Lunar and Other Rare Meteorites" annual auction of extraterrestrial specimens.
Christie's
In April, this Lemania watch -- given to Winston Churchill by the Swiss canton of Vaud -- was auctioned by Sotheby's in London.
In April, this Lemania watch -- given to Winston Churchill by the Swiss canton of Vaud -- was auctioned by Sotheby's in London.
Courtesy Sotheby's
In August 2016, Luxify -- a high-end auction house -- listed this dinosaur head online for $1.8 million.
In August 2016, Luxify -- a high-end auction house -- listed this dinosaur head online for $1.8 million.
courtesy luxify
Leonardo da Vinci's "Salvator Mundi" was once bought for $60, and is now billed as "the greatest artistic rediscovery of the 21st century."
Leonardo da Vinci's "Salvator Mundi" was once bought for $60, and is now billed as "the greatest artistic rediscovery of the 21st century."
JEWEL SAMAD/AFP/Getty Images
This rare 15th-century Meiyintang "chicken cup," still holds the world auction record for Chinese porcelain. It sold for more than $36 million (HK$281,240,000) at a Sotheby's Hong Kong auction in 2014.
This rare 15th-century Meiyintang "chicken cup," still holds the world auction record for Chinese porcelain. It sold for more than $36 million (HK$281,240,000) at a Sotheby's Hong Kong auction in 2014.
Aaron Tam/AFP/Getty images
In April, a collection of emeralds was a highlight of a jewelry auction Guernsey's auction house in New York. The emeralds were discovered on the Spanish shipwreck Nuestra Señora de Atocha, a galleon that sank off the Florida coast in 1622.
In April, a collection of emeralds was a highlight of a jewelry auction Guernsey's auction house in New York. The emeralds were discovered on the Spanish shipwreck Nuestra Señora de Atocha, a galleon that sank off the Florida coast in 1622.
Image: Courtesy Guernseys
On Sept. 9, this Ferrari Daytona sold at auction for $2.17 million. This is the only road-approved Ferrari Daytona to ever be made, and although it was missing for decades, it was auctioned off after being discovered in a barn in Japan.
On Sept. 9, this Ferrari Daytona sold at auction for $2.17 million. This is the only road-approved Ferrari Daytona to ever be made, and although it was missing for decades, it was auctioned off after being discovered in a barn in Japan.
ourtesy of RM Sotheby's
On Sept. 27, an auction of actress Audrey Hepburn's personal items went under the hammer at Christie's London. This included Hepburn's clothing and jewelery.
On Sept. 27, an auction of actress Audrey Hepburn's personal items went under the hammer at Christie's London. This included Hepburn's clothing and jewelery.
Fascinating objects found at auction

It is “extremely rare” for authentic lunar samples to be put up for public sale, Sotheby’s said.

“These samples are subject to laws governing public gifts, and in most cases, as in the United States, the law does not currently allow for public gifts to be transferred to an individual,” they added. “As such, this is the only known, documented lunar sample to have been gifted to a private individual.”

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The Luna-16 probe drilled a 35-centimeter hole in the moon’s surface to retrieve the fragments, which were gifted to Nina Ivanovna Koroleva by the USSR in recognition of her late husband’s contribution to the country’s space program.

Oliver Barker, Sotheby's European Chairman, fields bids for Andy Warhol's "Self Portrait" from 1963-64, during the Contemporary Art Evening Auction at Sotheby's on June 28, 2017 in London, England.
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03:09 - Source: CNN

Sotheby’s had previously sold the rocks for $442,500 in 1993, after Koroleva put them up for auction.

Previous objects retrieved from the moon have proven equally popular. Last year, Sotheby’s sold a bag used by Neil Armstrong to collect lunar samples during the Apollo 11 mission for $1.8 million.

The bag had been bought for just $995 only two years before, and a legal battle ensued when NASA discovered its provenance.

NASA owns around 842 pounds of moon rock, retrieved from six Apollo missions between 1969 and 1972.