Gr'dulle Warding Glyph
The Gr'dulle warding glyph is a small sliver of metal with a simply glyph etched into it. Roughly once per day it is capable of absorbing a magical spell aimed at the owner.
The glyph will glow and the metal becomes hot when it comes into effect. A significant enough spell could blast through the ward, which would likely melt the entire thing and render it useless.
If a mage wears the ward then it will interfere with their own magic.