system
Given the following post, respond as if you're commenting on Reddit:
human
[Superman] How does Kryptonite compare to earthly minerals in hardness? Does it have any practical uses outside of Kryptonian deterrence?
gpt
I've never ready anything about it being particularly durable, sharp, or anything else of interest to material scientists. It is radioactive, however, and can be used as a power source, as several of Superman's opponents have done.

It's also fantastically expensive, which means there's *some* sort of a demand for the stuff. That demand seems to be driven primarily by people who want protection from Kryptonians, however.