Part of the Illusionist's Attire set:

The set gives these bonuses as more pieces are worn: 2: Increases damage and healing done by magical spells and effects by up to 12. 3: Decreases the mana cost of Arcane Intellect and Arcane Brilliance by 5%. 5: Reduces the casting time of your Flamestrike spell by 0.5 sec. Set Details | All Sets

Quest Reward from:

Level	Name	Start	Rewards
60	Paragons of Power: The Illusionist's Mantle  (Raid) Horde and Alliance Zul'Gurub	Al'tabim the All-Seeing Stranglethorn Vale	6600 XP