There Was No Pearl Swap: One of Steven Universe's Most Popular Theories

You can't be blamed for watching Steven Universe and thinking that, just maybe, Pearl used to belong to White Diamond. A white-skinned Gem with her gem in her forehead? What does Steven Universe want you to think, anyway?
Well, White Diamond doesn't need a Pearl to feel superior to; the only reason she ended up with one was to punish Pink, and to give her a more sensible one-that is to say, one that was just as rigid as she was. It's a good thing for Steven Universe that White failed on that one too, because Pearl turned out to be more than she could have ever imagined.