Wreath of Lightning is a Legendary Gem in Diablo III. It can only be socketed into Amulets and Rings, and drops from Greater Rift Guardians. This gem works similar to a Conduit Pylon, striking enemies and destructible objects within 40 yards of the character every second for the duration. The effect does not stack, only being renewed. Upgrading only increases the damage of each lightning bolt. At rank 25, it also increases movement speed while active.