| || Ah...my name is — Berry. Of Bushtown.
The following information is based on the Deltora Quest anime and not considered canon.
The Nullifier Gem is a magic object introduced in the Deltora Quest Anime.
Zeean gave the nullifier gem to the companions as thanks for freeing the Torans from the Guardian's magic. Jasmine wore it on her person until the pyromancer Oacus attacked the group on their way to Withick Mire. As he was about to kill them, the gemstone released its magic, weakening the sorcerer enough for Lief to kill him. Afterwards, the gemstone disintegrated.
The gem is a small purple gemstone — possibly an amethyst — cut into the shape of a diamond, and surrounded by a silver border.
The gem is said to have been enchanted with Toran thoughts. When the bearer of the gem is in a time of great need, it emits a large wave of magic that reduces the power of any enamies of the bearer, and blocks incoming magical attacks. The gem's power is single use, and after a time, it turns to dust and vanishes.