Null Stone

Those with the witch-sight see this as a dark void, an unsettling patch of nothingness in the world of magic.
No Wizard within 6" of the bearer may cast any spells. No other magic item or rune item within 6" of the bearer will work. Treat them as normal weapons, banners, etc, of the appropriate type. Note that this applies to all friendly wizards and magic items as well as enemy ones.