Design: Flashing Crimson Spinel (loot)

Source
This design may be obtained as an epic drop from the five bosses in Hyjal Summit:
 * Archimonde
 * Azgalor
 * Anetheron
 * Kaz'rogal
 * Rage Winterchill

Related Sources
The Shattered Sun Offensive also sells this design. See Design: Flashing Crimson Spinel (Shattered Sun Offensive).