Taeguk is a Legendary Gem in Diablo III. It can only be socketed into Amulets and Rings, and drops from Greater Rift Guardians. This gem gradually increases damage as the player casts channeled skills (even if they do not hit anything), although for a very brief time, stacking multiplicatively with other similar modifiers. The buff stacks up to 10 times. Upgrading only increases the damage bonus per stack. At rank 25, it also causes adds an Armor bonus for every active stack.