Rockart Oval Nero Marquina is a 10" x 11" natural stone mosaic. Marble-look porcelain carries the veining without the sealing, etching and acid sensitivity of quarried stone. Natural stone varies piece to piece, which is what gives a floor its depth, and wants sealing on installation. It suits walls and light-traffic areas. Supplied on mesh sheets, so it follows a curve and cuts around an outlet without the tile having to be scored. Order the area you are covering plus about ten percent for cuts and waste.