Zenn3k said:
Actually in a wild case of research brilliance, Valve is correct in that assertion.
Lunar soil somewhat closely resembles a silicon/alumina asbestos-like contaminant in its effects on human contact- other than that, it's a lot like concrete, which is why research is being conducted on its effectiveness as a building material for a permanent Moon base.
Seriously though, why are moon rocks such a tightly controlled substance? Can they actually create portals or something? It's just a hunk of space dust. Who cares if someone wants to sell it or buy it for some exorbitant amount?
Because they're freaking rare and hard to re-aquire. The only moon rocks humans have, were gathered by Apollo 11, 12, 14, 15, 16 and 17 between 1969 and 1972. Man has yet to go to the moon since. The total amount is somewhere about the realm of one ton.
When Cave Johnson said "7 million dollars of moon rocks" that's a pretty ambiguous statement since each one of the Apollo missions brought back an average of 100 pounds, and each mission cost about 4 billion dollars (unadjusted for era)