Yes, Marrone Breccia Marble can be waterproofed. Marble is a porous stone and can absorb water if left untreated. However, to make it waterproof, the marble needs to be sealed with a high-quality stone sealer suitable for outdoor use. This will help prevent water penetration and potential damage to the marble terrace. It is recommended to consult with a professional stone installer or supplier for the best sealing product and application method for Marrone Breccia Marble.