Oh my Halone, not this ***again.
IDK, Sableye has 3 gems on its back. A Ruby, an Emerald, and a Sapphire... in another game I could see Sableyes gems all being about the size of the ruby, except hovering around him. Ruby could show animations when he attacks, Sapphire when he uses healing moves/Defnesive moves, and Emerald when using status moves.
But that'd be a lot of programming for a Pokemon game, still, significantly more epic sounding.
At the very least the gem coulda been more of an Alexandrite/luminescent so it can shine with the 3 colors of the one on its back. (Maybe it does do this, changing colors based on a forme we don't know of yet.. It'd be cool if the Gem he's holding did change based on what move he used last)