Lapis is the most dangerous gem on Earth. She's overpowered and definitely has some loose screws by now.

Jasper is an asshole, but they can deal with her on her own.
Lapis is emotionally unstable, doesn't give a shit about anything or anyone on Earth but Steven and can't be stopped by force if she goes on a rampage.

Gem shattering has been built up to for a while now, but we've never seen more than a crack. Someone has to be the first, and it might as well be the most dangerous gem on Earth.