This plain black iron ring is set with a single perfect diamond.

You can ignore the blinding effect of positive-dominant planes, such as the Positive Energy Plane. You also do not gain the fast healing ability usually conferred by such a plane, nor do you gain additional hit points when you reach your normal maximum.
Furthermore, spells that channel positive energy—typically cure spells—have no effect on you.

Prerequisites: Forge Ring, protection from positive energy (LM 70).
Cost to Create: 18,000 gp, 1440 XP, 36 days.