Cerussite

Cerussite is a form of metal that has been found to protect humans from the effects of "Dark Magic" and the Feywilds. Though expensive and heavy, this metal can be fashioned into protective garments by skille craftsman. It is a major export of the Western City-State Confederacy.
This material is vitally important to human and dwarven nations, who need cerussite armor for certain military actions into the dark magic wastelands.  Nowadays, these military actions are usually taken against orcish tribal settlements.