Auction: the only moon rocks retrieved from the lunar surface that can be legally sold

In the United States, it's illegal to buy and sell moon rocks retrieved from the lunar surface during the Apollo missions. However, the law doesn't apply to the tiny moon pebbles seen above that a Soviet robotic probe drilled out of the lunar surface and sent back to Earth in 1970. In 1993, Sotheby's auctioned these 'Soil Particles From Luna-16' off for $400,000. Now, they're going on the block again and expected to go for twice that amount or even more. According to Sotheby's, 'the sale will mark just the second time that an actual piece of another world has ever been offered for public sale.' From Collect Space:

The lunar samples were originally presented by the Soviet government to Nina Ivanovna Koroleva, the widow of Sergei Korolev, the 'Chief Designer' of the Russian space program. Under Korolev's direction, the Soviet Union successfully put the world's first satellite into Earth orbit and launched the first human into space. His unexpected death in 1966 came before he could see the outcome of the space race to the moon.

Four years after Korolev died, the Soviets launched Luna 16, the first of three robotic lunar sample return missions. Touching down after the U.S. Apollo 11 and Apollo 12 astronauts had come and gone from the moon, Luna 16 deployed an extendable arm to drill and extract a core sample 14 inches (35 centimeters) deep. The 3.5 ounces (101 grams) of soil and rocks that it collected were then deposited into a capsule for their return to Earth.

The display gifted to Koroleva contains three grains of the Luna 16 material, weighing about 0.0007 ounces (0.2 grams). The central fragment is basalt, typical of the moon's mare (or 'seas') terrain while the adjoining two larger fragments are regolith with glass coatings caused by an micrometeoroid impact, according to Sotheby's.

More at Sotheby's: 'Returned to Earth by the Soviet Luna-16 Mission in 1970, the Only Known Documented Moon Rocks in Private Hands Come to Auction'