Soak a piece of superfine steel wool in clear water.
Pour water directly on the marble surface to lubricate it to prevent scratches. Don’t worry, water will not damage marble unless it sits too long.
Rub superfine steel wool over the ring until it is gone. Rub in circular motions around the ring to blend it with the surrounding marble.
Sprinkle polishing powder over the area if you can still see the ring. If the ring is still visible, it is most likely because the water etched the marble surface. In this case, you’ll need to polish out the etch marks.
Scrub the polishing powder into the marble with a damp cloth. Rub in circular motions until the mark is gone.
Rinse the area with water and dry it with a clean cloth.