Grease Magic Grout & Stone Sealer is a water-based penetrating sealer. It protects natural stone surfaces from staining, and can be used on countertops, floors, walls, and grout! Grout & Stone Sealer absorbs into the surface of the tile/grout, and forms an invisible water AND oil-based stain repellant barrier, while still allowing the surface to breathe. This product is non-flammable, does not release any ozone-depleting materials, and does not release formaldehyde. Use on marble, terrazzo, slate, granite, porcelain, brick, concrete, limestone, stucco, grout, terra cotta, and ceramic tile. Always pre-test!