And now for something completely different

From DC Comics, an example of life imitating art, or something like that. Though I'd be more impressed if the rock was a glowing green. ....

"A new mineral, matching the chemical composition for kryptonite suggested in ‘Superman Returns,’ was discovered by a team of geologists in a Serbian mine, according to London’s Natural History Museum. Unable to find a suitable match to a known mineral, the geologists turned to the Internet, which revealed the rock’s relation to the most famous element in comic books.

"The real world version of kryptonite – which according to media reports will be officially named 'jadarite,' after the place where it was discovered and because it does not contain the element krypton – is white, does not glow and is reportedly harmless to humans and/or natives of the planet Krypton."