Marshalltown Rubbing StoneMarshalltown Single Sided Tile Stones and Rub Bricks are used to smooth and dress down newly cut tile. You have your choice of various sizes, grits, and color. Our white Tile Stones and Rub Bricks are made of aluminum oxide and don't mark tile. The black Tile Stones and Rub Bricks are made of silicon carbide. Used to smooth and dress down newly cut tile Choose your size, grit, and color White Tile Stones and Rub Bricks don't mark tile