Design: Shifting Shadowsong Amethyst (Shattered Sun Offensive)

Source
This item is a reputation reward; you must be with the Shattered Sun Offensive to purchase it for  from  in Sun's Reach Harbor on the Isle of Quel'Danas or from  in Shattrath City.

Related Sources
Bosses in Hyjal Summit also drop a version of this design. See Design: Shifting Shadowsong Amethyst (loot).