Item from The Wheel of Time by Robert Jordan
The Sword That Is Not a Sword — a crystal sa'angreal that amplifies the One Power to devastating levels, but has a fatal flaw: it lacks a buffer, and it can be turned against its wielder.
Callandor is one of the most powerful sa'angreal ever created and the focal point of multiple prophecies. It was placed in the Stone of Tear specifically so that the Dragon Reborn would draw it, fulfilling prophecy. Its flaw — the lack of a buffer against drawing too much Power — makes it dangerous to use alone. In the end, it was wielded by Rand in a circle of three (two women, one man) to seal the Dark One's prison, turning the flaw into a feature. The prophecy that the Stone would never fall until the Dragon came made Callandor the world's most elaborate proof of identity — drawing it proved Rand was the Dragon more convincingly than any other sign.
A sword made of crystal that glows with inner light — it looks like a blade of frozen lightning. It floats in a column of light when displayed and pulses with power when held. It's beautiful, impossible, and vaguely unsettling — a weapon that looks more like an art piece.
Also known as: Callandor, the Sword That Is Not a Sword, the Crystal Sword