You can, as a matter of fact, wash your pampered Chef Pizza Stone. Wash the stone under hot running water, while scrubbing with the pan scrubber or a sponge with a nylon scrubbing surface. Soap should not be used. Check out www.ehow.com/how_6064288_pizza-stone-care-instructions.html for details.
Thorsmama is slightly off-base, in regards to Pampered Chef baking stones. They indeed CAN get wet, and they do not absorb water. HOWEVER, do not put your wet stone into a hot oven to "dry it faster". It will indeed crack.