Special Materials
Any item made from these materials is considered masterwork. As such, you must pay the masterwork price in addition to the costs listed below (+300 gp for weapons, +150 for armor). Weapons get a +1 to attack (unless an enhancement bonus is listed below) and armor gets a reduction to armor check penalty of 1 (unless a greater armor check penalty reduction is listed below).
To work out the cost of the item, multiply the normal weight of the item by the cost increase listed for the special material.
Adamantine
The rarest (and therefore most expensive) material.
Weapons: masterwork bonus, 1d4 and 1d6 weapons get a +1 enhancement bonus, 1d8 and over weapons get a +2
Armor: masterwork bonus, light armor gets +1 armor enhancement, medium +2, heavy +3, shields +1
Cost: +700 gp/pound
Hardness: 20
HP/inch: 40
Weight: same as steel
Darkwood
Weapons: masterwork bonus, greater mighty bows are possible:
mighty shortbow +3: 450 gp
mighty longbow +5: 800 gp
mighty longbow +6: 1000 gp
Armor: masterwork bonus, armor check penalties for shields decreases by 2
Cost: +30 gp/pound
Hardness: 7
HP/inch: 15
Weight: 1/2 normal
Gold Steel
Weapons: masterwork bonus, +2 to damage
Armor: masterwork bonus, armor check penalty decreases by 4, max dex bonus increases by 3, armor is considered two categories lighter
Cost: +400 gp/pound
Hardness: 20
HP/inch: 35
Weight: 1/5 of steel
Ironwood
A strange combination of wood, iron, and magic. Ironwood is twice as hard as other woods.
Weapons: masterwork bonus, +1 to damage
Armor: masterwork bonus, Ironwood does not burn or even heat up giving a fire resistance of 5
Cost: +50 gp/pound
Hardness: 10
HP/inch: 20
Weight: same as wood
Mithral
Weapons: masterwork bonus
Armor: masterwork bonus, spell chance failure 10% less than normal, max dex bonus increases by 2, armor check penalty decreases by 3, armor is considered one category lighter
Cost: +100 gp/pound
Hardness: 15
HP/inch: 30
Weight: 1/2 steel