This is a super cute idea! And I love the little backstory you came up for the image. Very creative! I have a couple characters I think I'm going to go Gem-ify for fun now.
In my case however I'm just going to do a crossover. I have a pair of characters named Scarlet and Sapphirine. Was thinking it would be fun to have them cosplay as Ruby and Sapphire.
In any case, love your work as always and yay for more people who watch Steven Universe! It's such an awesome show.