Rose Quartz's past has been a mystery since the first episode of the series. Actually, even herself is. From being mentioned by Amethyst in Laser Light Cannon to fighting gems as rebels in The Answer, we have enough facts to conclude why Rose Quartz is not Pink Diamond.
1) The Rebellion Illusion
As a strong quartz, Rose has been respected by gems in Homeworld even before the rebellion. She was looked up to as a very strong warrior. What made her look more powerful and strong was when the rebellion started. Little is known about it but in victory, to our eyes, Rose Quartz looks really strong and a bit of ruthless, despite her loving and motherly personality. We all know that Rose Quartz defeated the Diamonds, convincing us to believe that she is Pink Diamond. But what if, they just really used fusion to defeat them?
2) Removal of the Pink Diamond
In the episode Jail Break, we saw parts of the gem warship. A part of it acted as an ring for Jasper and Garnet. While Garnet was singing the never-dying hit "Stronger than You", we all saw the authority sign for the Diamonds. We continue to see this sign in the second season. In Sworn to the Sword, we see the sign, butt! the triangles were diamonds and there was a new diamond added to it, a pink diamond. Fans theorized that it was removed prior to the rebellion led by Rose, creating a sub-theory that Rose is Pink Diamond. Butt what if Rose was just a member of Pink Diamond's court? The other diamonds blamed Pink Diamond for letting the rebellion happen? By the way, reasons to why the pink diamond was removed is not yet revealed.
3) Height Matters
In Message Received, we saw Yellow Diamond (her neck really bugs me). She is very tall and very tall compared to Yellow Pearl, who is just looked down by Yellow Diamond as an ant. Compared to Rose Quartz, we know who's taller.
4) Read Description
Obviously, Rose is a Quartz. How can she be Pink Diamond? Unless she changed it to distinguish herself from the Diamonds, looked upon to be very ruthless.
Will you fight for your right?! If you will, comment! If you agree, comment.