We recently completed a project a restoration project in the GTA on a polished marble (Crema Marfil) floor with granite accents (Nero Assoluto) . The floor was sanded to remove scratches in the floor from foot traffic and moving chnairs in/out from the dinning room table. There were a number of etch marks (dull spots) on the floor from spills that we removed during the sanding process. The entire floor was brought up to a high polish and the stone and grout were sealed to protect the floor.
For more information about Etch Marks and Wear on natural stone floors, please follow the attached link: http://marblerenewal.ca/most-common-surface-problems/