What is grinding and polishing marble with natural stone?
You can polish anything, using anything which is harder. Marble is a relatively soft stone, and if you used another type of rock to polish it, it could work but would take a long time. We use to use a quarts based stone, but these polishing stones are quite thick, needed lofts of water and left a really big mess. Sandpaper is a small amount of quartz sorta glued on a piece of paper or canvas. Not very practical when polishing large amounts of marble like an entrance floor, but would work on smaller pieces ot statues. Today we use industrial grade diamonds. That plastic, Number 1 was taking about is just that. These diamonds are embedded in a resin, melted together to form a diamond pad. These diamond pads which comes in different grits can bring the highest amount of shine in a marble when used properly. The last step is a powder, which is usually based of Oxalic acid, potassium, and other “fun stuff”, and this brings out the final mirror finish.
