SO HEY all of a sudden I know how to handle Rhódon — and the way she got reincarnated — in the Gem AU.
First, back in the era of legend, the nation-founding warrior-queen is a bicolor Chameleon Diamond. Specifically, this bicolor diamond, which looks deep green from above, but is more of a silvery-grey when viewed from the side.
Her true love is a Millennium Star Diamond. Millennium wasn’t officially an equal co-ruler, but she’s iconic enough that her four-pointed star symbol is what ended up on the uniforms of all the present-day knights.