While masterwork weapons are available from any skilled craftsman, the dwarves have perfected their skills to an almost magical degree. They possess secrets of smithing and weapon engineering that outstrip cultures that are less challenged by both their natural environment and competition for its limited resources. While many dwarf weaponsmiths and armourers are capable of crafting masterwork items, as normal, dwarf smiths have created another category of quality that goes beyond masterwork. Appropriately, such items are generally referred to as dwarvencraft items.
Dwarvencraft items are always of masterwork quality. Only items crafted primarily of metal or stone are available in dwarvencraft quality. An item must be declared a dwarvencraft item at the time of its creation; items cannot be upgraded to dwarvencraft quality once finished. Dwarven craft items are crafted using the rules for masterwork crafting. The dwarvencraft component of an item has a Craft DC of 22. Prices for dwarvencraft items include the cost for masterwork quality.
A dwarvencraft item is stronger and harder than a comparable masterwork item. A dwarvencraft item’s hardness increases by 2, and it gains an additional 10 hit points. In addition, it gains a +2 bonus on all saving throws. All of these effects stack with the similar bonuses for magic items if the dwarvencraft item is made magical.
A dwarvencraft weapon costs 600 gp more than a standard weapon of its type. Dwarvencraft armour and shields cost 300 gp more than standard armour and shields.
Source: Races of Stone (Page 159)