The official GemStone IV encyclopedia.
White ora is slightly rarer than regular ora, and is more valued. It has the same basic properties as common ora, but it has the unusual natural ability to harm the undead under the right conditions. Through much study of this strange variant of ora, it is said that the magic within the metal reacts to the aura of a cleric or paladin, becoming sanctified in their hands. This allows them to wield it against undead beings without the aid of blessing magic. When held by other professions, white ora must still be blessed to bypass undead physical resistance.
It is the polar opposite of black ora.