A woman who tried to sell a rare chunk of moon rock for $1.7 million U.S. (1million) was caught out when her prospective customer turned out to be an undercover Nasa investigator. It is illegal to sell moon rocks, which are considered national treasures. The grey rocks, which were gifted to each US state and 136 countries by then-President Richard Nixon, can sell for millions of dollars on the black market. Nasa agents and Riverside County sheriffs deputies detained the woman, who was not immediately identified, after she met with an undercover Nasa investigator at a restaurant in Lake Elsinore, south-east of Los Angeles. The investigation was conducted over several months. Authorities swooped after the two agreed on a price and the woman pulled out the rock. Nasa planned to conduct tests to determine whether the rock came from the moon as the woman claimed. 'We dont know if its lunar material, said Gail Robinson, deputy inspector general at the space agency. Joseph Gutheinz has spent years tracking down missing moon rocks, said a lunar curator at a special lab at Johnson Space Centre would carry out the testing. The woman has not been arrested or charged. It was unknown how she obtained the rock or came to the attention of Nasa. MO