The Diamond Turtle is a diamond fashioned in the shape of a turtle. It was created and used by the Cows.
The Turtle was first created by the Cows 2000 years before the events of Angry Birds. The Turtle was used to create the islands Bird Island, Piggy Island, Golden Island, Eagle Island, All Terra, and Isle Cirrocumulus.
During the events of Angry Birds 3: The Final Flocktier, the Diamond Turtle was shattered in battle and was collected by the Pigs. The Pigs used it to summon the Cows. The Diamond Turtle was then used to split All Terra through the middle. After it was used as a power source.