[Miscr3ant]

And thank you DM Carcass for explaining further. It seems that gems function much like the forge system. So, if I have STR and DEX on a helm, I can add a +1 Fort gem. However, even though according to the toolset value I can place another Fort gem on the item, due to how it is applied, I get the error stating that the item has too many properties. So, I would have to remove my STR (for example), place the gem on, then add the STR back to the Helm.