Polished natural stone has a shiny, reflective finish as opposed to the matte, dull finish of honed stone. Polished stone is sanded with finer and finer grades of sandpaper until a glossy finish is achieved.
When grouting polished natural stone, use an unsanded grout such as MAPEI Keracolor U. Adding MAPEI Grout Maximizer to MAPEI Keracolor U will help to reduce the porosity of the grout and help to keep the grout clean. If a sanded appearance is desired, a colored quartz (CQ) grout such as MAPEI Flexcolor CQ can sometimes be used successfully, but a test panel should be grouted and inspected for unacceptable scratching before grouting.