Someone else brought this up in a different thread, but didn’t Hades enchant a chisel, not Hook’s hook, in order to carve the names onto the tomb stones? *sigh*
I thought the same, until I actually re-watched the scene. Hook actually never said that Hades enchanted his hook to carve the names. He said that “he enchanted my hand to carve these markings in the first place”. Back in the episode “Labor of Love”, Hades shows the hook to Emma, and drops it on the ground before leaving. This took place before Hades asked him to chisel names, too. Hook continues to be hookless until Emma saves him in the “Devil’s Due”, so I’m guessing Emma kept the hook and returned it to him. So I think the enchantment was done to Hook’s hand, and that was what gave him the power to carve names, rather than the chisel itself.