So like I said earlier, Rose used to be Pink Diamond. But why has her skin tone changed?? I believe that Rose Quartz is a fusion. I'm not quite sure what gem she fused with but my friend pointed out to me that there's a bubbled gem inside of lion. That could possibly be who Pink Diamond fused with. I also noticed that when Garnet from the answer appeared in front of the rebels, Rose Quartz was there since her skin was paler and she seemed a bit taller than she was earlier.