Water left standing on a polished granite counter until it evaporates leaves a mineral residue behind to stain the smooth surface. While the white stain is unsightly, especially on a dark-colored granite, a quick polish with 0000 steel wool removes the hard water stains without further marring the finish.
Polish It Off
Gently buffing the stain with a dry 0000 steel wool removes the accumulated mineral deposits without damaging the polished surface of natural stone. Blow or brush the dislodged powdered minerals away. Avoid using any acidic cleaner, even household vinegar or ammonia, as it may dull the finish on the countertop.
Prevention Is Worth a Pound of Cure
Prevent hard water stains by blotting up all water spots immediately. If the countertop is dirty, wipe it with a soft, damp cloth. Wipe the counter dry with a second cloth to prevent water spots. Using coasters and trivets while cooking also helps prevent water spots and scratches on granite countertops.