Armageddon Sapphire

The Armageddon Sapphire was a superweapon created by the Time Lords and stored in the Slaughterhouse on Gallifrey.

They were considered the ultimate weapon used by the Gallifreyans which was capable of tearing reality apart thus causing the Higher Place to collapse into Calabi-Yau Space. (PDA: The Quantum Archangel)