Would a Gem ever make her default form cover her gem? The outfit Amethyst is wearing in the old-timey picture does this, but maybe it was a shapeshift? It would make it difficult to get her weapon out quickly. Are there any reasons you can think of for why a Gem would form herself in a way that covers her gem? Might it be a little better protected, perhaps if she was lower on the Mohs scale (though Amethyst is pretty high on it)?