We've all heard the theory that Rose Quartz, leader of the rebellion, is none other than Pink Diamond. Now, this theory was disproved, because the newer episodes say that Rose Quartz shattered Pink Diamond, but I've decided to look at this age old theory from a new perspective anyways.
Original TheoryThe murals in the moon base show all of the Diamonds: Yellow, Blue, White, and Pink. The Pink Diamond mural shows her with large hair and her gem on her navel. Rose is shown in a similar way through the series, a navel gem and large hair. Both are based on pink gems and are linked to the Earth in some way. Pink Diamond ruled over the Earth and controlled gem production there. Rose was created on Earth and fought for its protection from Homeworld.
Pink Diamond rebelled against Homeworld, trying to stop the other Diamonds from destroying Earth. The other Diamonds banished her, removing her symbol from the insignia. This theory was debunked after it was stated that Pink Diamond was shattered by Rose, but I'm going to shed a new light on this premise.
If gems can shapeshift, shown often by Amethyst, then logically higher ranking gems such as the Diamonds can shapeshift as well, possibly to an even greater extent. Rose is also known to keep a lot of secrets from even her closest friends, and the defending Zircon during Steven's trial did have a good point of not being able to shatter a gem with a sword.
Pink Diamond may have seen Earth's beauty, and staged her own death, shattering one of her own Rose Quartzes to use the shards as a deception. Pink Diamond shapeshifted into the Rose she shattered, starting a rebellion against Homeworld. Homeworld is left believing that Pink Diamond was shattered by Rose, and even the rebellion believes the tale.
So, what do you think? This is my first real theory, so don't be surprised if it gets disproved. I mean, why would Pink Diamond of all gems give up their physical form, and how would the other Diamonds not be able to tell a Rose Quartz from a Diamond? A Ruby couldn't tell an Amethyst from a Jasper, but a Diamond surely could, right? That's it for this theory, leave your thoughts in the comments.