Travertine is one of the most porous stones available. This is not good for countertops! These countertops stain quite easily and then you are stuck with it. Travertine is very predisposed to acid. Acid will etch the surface and stain it. Lemon juice will even mar the surface of the counter. You are not to leave any liquid standing on the countertops, even water, for a short period of time because it could sink in and stain. Travertine countertops require a lot of regular sealing applications to keep them from staining. Even putting Travertine in a bathroom is a bad idea because many soaps/skin creams are going to stain/etch it Travertine is porous, and easily stained and is etched by acids. Avoid setting beverage glasses directly on Travertine as they leave rings. Fruit juice, carbonated beverages or other acids will etch (remove shiny surface) if allowed to remain on marble. Wipe up acid spill immediately, and wipe surface with wet cloth. If surfaced is etched, polishing may be required.