In addition polishing grit or marble dust will fill.
Wet sand marble countertop.
Before you sand or grind a marble surface fill in any small cracks.
Another traditional method to restore the gleam of marble countertops is to polish them with baking soda.
Start with the coarsest grit sandpaper you have.
Spray a penetrating stone sealer on the marble countertops until the surface is wet.
Mix three tablespoons of soda with one quart of water and apply it on the surface then let air dry for several hours.
Wrap it around a block of wood or sanding sponge.
After washing it with warm water wipe crushed chalk on the countertop rinse again and dry with a chamois cloth.
For small blemishes uses 400 grit.
Grinding unrepaired cracks will cause the edges to chip creating holes.
Saturate the surface of the marble countertop a second time and wait 30 minutes.
Allow the sealer to sit on the surface of the marble for up to five minutes.
Note use 220 when trying to smooth out irregularities.
Wet the surface of the marble with a spray bottle.
Wet the surface of the sandpaper and marble.
Fill a clean spray bottle with plain water and spray a light coating of water over the marble.