So I recently stole the Ancient Nord Amulet from the Jarl of Falkreath and much to my dismay I can't seem to add any enchantments to it. Is it because it is stolen or because the code is broken?

Some items can't be enchanted. If they are named, even though they have no obvious enchantment on them, it's a pretty good indication that you can't enchant them.

Damn shame. Only unenchanted amulet that fits my character and the thing is incapable of being enchanted. What is the point of even having it in the game?