Arsenic and mercury, both commonly occurring metals present in rocks, can kill humans immediately. Especially if vaporized. Uranium can kill and disable quickly in high enough concentrations.
Also, keep in mind it’s a plot device about a fictional flying space alien with laser eyes. It doesn’t need to follow the laws of physics.
But then they’re not rocks. It’s a vapor or a metal. That also actually disqualifies uranium as well since the rock isn’t what’s dangerous, it’s the radiation that destroys your cells. With Superman it’s literally just a rock.
Arsenic and mercury, both commonly occurring metals present in rocks, can kill humans immediately. Especially if vaporized. Uranium can kill and disable quickly in high enough concentrations.
Also, keep in mind it’s a plot device about a fictional flying space alien with laser eyes. It doesn’t need to follow the laws of physics.
But then they’re not rocks. It’s a vapor or a metal. That also actually disqualifies uranium as well since the rock isn’t what’s dangerous, it’s the radiation that destroys your cells. With Superman it’s literally just a rock.