Steven Universe - Deception

As gems, as well as organic haters, they wouldn't need to need trees or grass for air, so it's likely that Homeworld has no oxygen. Without oxygen, flames wouldn't be able to sustain its form, so it would make sense if Peridot has never seen raw fire before.

Wow, I thought up all that from just one comic.

ah but she did see flames when her hand ship exploded