Ok, new artifact:
Utility Artifact: The Codex of Arcana
A large tome made of what seems to be very old parchment bound in sturdy leather studded with white shining metal. On its cover is Alether's sign, the hand with a crystal in its palm and a 13-sided star surrounding it. The sign is made out of purplish slightly glowing ink.
The artifact holds the secrets of accessing and controlling the Eldritch powers locked in the Magic Realm. Only mortals can use this artifact, and gods trying to use it will find it impossible to open the book or read anything from it even if a mortal opens it for them.
To use Arcane magic, a mortal must intensively study the writtings in the book. It takes incredible intellect and perceverance to master even the tiniest powers, so only the best of the mortals can learn to control magic. Furthermore, the Codex must remain with the mortal who learns magic at all times if he does not want to lose his powers. If the Codex is stolen or otherwise taken from the mortal who knows the magic, his magical knowledge starts to fade after one week and completely dissappears after a length of time proportional to his magical prowess. Thus, an apprentice might lose all his knowledge in a week, while the greatest of wizards might hold on to a speck of power for up to a decade if not more. To regain power thus lost, the Codex must be retreived and studied for an amount of time equivalent to the ammount of time it took for the powers to fade.
Even though the Codex must remain with one individual for him to retain his powers, it is possible for others to learn to control magic at the same time, if the one that owns the Codex is willing to allow them to study in the Codex and maybe teach them too. (ie. a wizard would take apprentices). There is definitely a limit to how many may study the Codex at the same time, as all who want to learn magic must study in it for extended periods of time, and all who learn in this way must also 'visit' the Codex atleast once a week to not lose their powers.
Finally, learning magic extensively would take many millenia, but controlling magic does increase the natural life of the student, thus allowing him more time to master the Art. However, many apprentices are killed during the learning process, wether because of wars for the Codex or because of magical mishaps.
I'd say this artifact costs 3AP, since all it does is give access to mortals to Arcane magic which is my domain.