[Bolding mine.]
If true, which I seriously doubt, this would be a violation of federal law. To be clear, I’m not accusing @Omar_Little of lying, but either his friend or her grandfather is not telling the truth.
From here:
The federal government forbids private ownership of any Apollo sample.
No lunar samples are “given” to private individuals. Each piece of the Moon returned by the Apollo astronauts is carefully accounted for and resides in the Lunar Curatorial Facility in Houston, where they are kept in two separate hurricane-proof vaults.
The only way there might be an element of truth to the claim is if the “rocks” are in fact bits of dust.
It was rumored for years that several of the Apollo astronauts held samples from their respective missions. If they did, it was probably inadvertent—the lunar dust is extremely adhesive and it is possible that smudges of lunar dust clung to personal items returned from the Moon in their Personal Preference Kits.
Those Personal Preference Kits were inspected after the missions, so there is no way anything larger than a bit of dust could have slipped through NASA’s hands.
Have you seen the “moon rocks”?
As the article points out, the government takes the matter of private citizens holding moon material very seriously, so if your friend really had such material, it would have been very careless of her to mention it to anyone. And since only 18 men were on a moon-landing mission and had personal contact with moon rocks, and those 18 had a finite number of grandchildren, anyone who wants to investigate the claim doesn’t have to look too far, so your attempt at protecting their identities is pointless.
The most plausible explanation I can think of (apart from an outright lie on the part of your friend) is that grandpa gave her a few chunks of earthly basalt, perhaps picked up during a training mission, and told his young granddaughter he brought them back from the moon just for her.