The Wavestone and The Woadstone

The Wavestone is in a swamp or beachy dungeon or shrine. It is a necklace and takes up the necklace spot. 

If worn by an arcane spellcaster, once per day, that character can forget a spell he has memorized and instead cast a different spell that he has in his spell books. No matter what, it will only work once per day. If you are a human Magic-User, it also grants a +1 to saves and to dexterity.

The Woadstone Relic is also a necklace. It will be in a deep forest or swamp dungeon or temple. It has a continuous effect. It grants the wearer +1 to armor class, +1 to saving throws, and +1 to damage in melee combat. Additionally, if the wearer is a Druid or elf, it grants a +1 to strength and constitution.