Lippage Removal or Flattening
Lippage is a condition where edges of the tiles or slabs are not at the same level with each other. A one way to determine this is by a thickness of dime when placing it to the edge of next tile and if the next tile is higher than the dime this can be considered lippage.
Before polishing marble floor any tile lippage should be removed and the surface made flat.
The best way for removing lippage is grinding down a marble floor by lippage removal discs and planetary floor machine.