Is it possible that Queen Aurora could have a gem counter like the trolls and some other units? This would certainly make it easier in choosing which gem colour to spawn.
There are other units that would benefit too, but been using her recently. Consistency across troops would be nice.
Or just always show all of them, and show them whether or not the spell is ready to cast. Less work on their end, more information on mine (sometimes it is good to know the count before I fill up the troop that it is “relevant” on).