"A world without evil? Boring. Give me vile fiends to smite and banish any day." —Sarlena, paladin of the Northern Verge
Official Rulings for Celestial Purge
10/1/2009 : Lands are colorless (even if their frames have some colored elements to them). You can't target a Swamp, a Mountain, or any other land with Celestial Purge (unless some other effect has turned that land black or red).