Hammer of the Armoursmith
An old blacksmiths hammer with a precious gem placed in the head.
This weapon does damage as a light mace and is considered as such for all intents and purposes.
Upon hitting a creature wearing armour that primarily consists of metal (eg, chain shirt, half-plate, full-plate) or metal shield, the armour/shield bonus (if any) of that piece of equipment is reduced by 1 to a minimum of 0.
In addition, any time spent crafting or repairing primarily metal armour using this hammer is halved.