Mage · Arcane · tier 2 · from level 15

Arcane Resilience

Rank 2/2

Increases your Armor by an amount equal to 50% of your Intellect.

Doesn't change the damage or healing of any Mage spell.

Averages, counting crits and misses, for a level 60 Mage with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.