Stone of Equilibrium: +500 Mana +50 AP +30 Magic Resistance UNIQUE PASSIVE: Grants bonus mana equal to 45% of your AP. UNIQUE PASSIVE: Upon reaching below 20% of your maximum mana, you regenerate 30% of your maximum mana over 8 seconds(120 second cooldown)
Cost: 2900(800)
Builds from: 
This would be a core item on champions like 
or 
It might need some tweaks, so feedback is appreciated!
Marthian1 votesThe big question is what niche would this item fill? Mana recovery? We already have Athene's Unholy Grail, Rod of Ages, Archangel's Staff. Raw mana? Rod of Ages and Archangel's Staff
Prospector Pete1 votesA mixture of the both. It's good when combined with the 2.
Wicked Waffle1 votesOh god, when this is combined with Archangel... More mana = more AP More AP = more mana Endless cycle.
Duke Anax1 votesSounds good at first glance and while I don't see much reason for it I don't really see anything against it.
However considering that Mana is a higher scaled stat than AP I would change the conversion a bit. more like 150% AP and to balance, set the base at 250 mana. That's 1000 mana at 500 AP.
If this turns out to be too much mana on Veigar or Cassiopeia it cqan be further tuned.
What I really like about it though is that it is a mana item with MR, we don't have one of those yet.
Squidblimp1 votesIt seems like you're trying to mix Archangel's Staff with Athene's Unholy Grail. Why not just buy both those items instead of this one?