D&Dtools1

The subject's natural weapons take on a gleaming, metallic sheen.
You temporarily transform one of the subject's natural weapons into either cold iron or silvered, thereby allowing it to bypass the appropriate form of damage reduction.
The affected natural weapon also counts as magical for the purpose of overcoming damage reduction, though it gains no enhancement bonuses on attack or damage rolls.
You can cast the spell twice on the same weapon to make it function as both cold iron and silvered.