Board Thread:General Discussion/@comment-26335243-20150418140548/@comment-508329-20150420143925

Gems have a sense of taste, and Fire Salt definitely wasn't designed for human consumption, so it was probably either something that one of the Crystal Gems invented on Earth after discovering Earth cuisine or something they had back on the homeworld.

The worm monster might've been eating glowing stuff because it thought the glowing stuff was magic. I'm guessing that some gem monsters might also be able to assimilate material from the environment (sort of like how the the Lighthouse Gem Monster from Horror Club possessed the lighthouse, or how some of the light creatures in Attack the Light make protective rock shells).