>>96400585Maybe? It's not confirmed. The problem is that gem bodies function a lot like crystal, since they're hard light projections. They're strong and light, but shatter rather easily. Gems poof from stabs that a human, being fully physical, could withstand at least temporarily. To use a comparison to Ben 10 again, it's the difference between Diamondhead the Petrosapien and The Worst the Atrocian. Diamondhead is very strong and his crystals are strong and sharp, but they shatter rather easily. The Worst is softish and still feels pain, but is practically invincible, taking damage similarly to how Flats hits Spongebob.
In fact, his gem powers combined with his healing spit mean that it's probably likely that Steven could survive being stabbed through the gut, rather than poofing or just dying.