This is done after the honing phase, and a series of higher diamond grits are usually used to simulate higher grits. Most natural polishing powders are known to contain the active ingredient oxalic acid, which is also known as potassium oxalate.
The polishing process is sure to give semi-shining or shining effect to the marble floor, and industrial diamonds do it, but smaller graded than that of honing. For marble floors in good condition a polishing can be enough to bring back the shine.