i think that the slot idea is a good one, but i think you should only be able to put gems in the slots when you smith them. and i think that you should only be able to put in 1 kind of gemstone. otherwise it would get too confusing to have, for example, iron platebody of magic, defence, attack, and so on. and on the enchant spell, it should only take 1 enchanting. and for those things that take 1 bar, i think u should have to smash the gem first, because the stone might be bigger that the object itself.