You transform the physical makeup of a weapon as you desire.

This spell functions like greater magic weapon, except that it subtly alters the physical properties of a weapon, enabling it to bypass damage reduction of one the following types: bludgeoning, cold iron, piercing, silver, or slashing. The affected weapon still inflicts damage of its normal type and its hardness and hit points are unchanged. This spell can be cast on a natural weapon or unarmed strike.