User blog comment:Justice Avenger/Crazy Theories!!/@comment-4821105-20120903161237/@comment-1038387-20120903185106

If they're near Green K, Kryptonians generally don't have enough strength to use their heat vision. But others can touch it or destroy it. But it's best if they don't destroy it - if you blow up Green K, all you get is loads of small Kryptonite shivers, even more dangerous than one big chunk.