The Diamond Authority of Ceannis decides to abdicate together. Chameleon Diamond gets poofed and re-forms, with her memories missing and her gem turned the other way, so nobody thinks twice when she introduces herself as Lettuce Quartz.
(A term that does actually have a few Google results. I'm as surprised as you are.)
After finding out her true identity, she keeps it secret for a thousand years, even from Mistel, her devoted Burgundy Pearl. But finally Lettuce gets sick of the replacement Authority being even more flawed than the original.
She reveals herself, re-takes the throne, and sets out to personally implement a democracy, instead of just hoping it would sort itself out once the Diamonds were gone.