Heavy weapons, such as those made from gold or platinum, are unwieldy, but inflict additional damage. Without the proper Exotic Weapon Proficiency feat (for example, heavy longsword), you suffer a -4 penalty on attack rolls with a heavy weapon. Only weapons made entirely or largely of metal (such as swords or axes) are affected. Other weapons (such as spears) are not.
Weapons made of a heavy metal inflict increased damage as shown on the table to the right.
A character can wield a heavy weapon one size category smaller than his own in two hands to avoid the attack penalty. For instance, a human wielding a light mace made of gold with both hands, or an ogre wielding a platinum longsword with two hands, does not suffer the attack penalty.
You can never use the Weapon Finesse feat with a weapon made of a heavy metal.