All our Fontane Bianche pieces leave the factory pre-sealed. Since we do not like to paint the surface of our lovely stones with transparent paints or resins, we apply three coats of the highest possible level of protective penetrating sealant. This will preserve both your piece and the natural feel of the stone.
That said, please bear in mind that there is no sealer on the market that can make a natural stone 100% stain proof, especially if you leave the staining agent on it for a prolonged period. The sealant allows you to have a few hours between the moment the staining agent (for example, coffee or perfume) comes in contact with the stone and the moment you wipe it off. So, if coffee somehow spills on your Fontane Bianche piece, you will need to wipe it off within a few hours to avoid permanent staining.
As far as maintenance goes, DO NOT use cleaners containing abrasive cleansers, ammonia, bleach, acid or even those “homemade remedies” made from lemon, vinegar and the like. Simply use water or a neutral detergent. It will be more than enough.