Marble and granite can both etch and stain. Etching is caused by acidic products, such as strong soaps or lemon, as well as milk. These can all leave a mark which looks like a lack of luster or a matte spot.
These etch marks are removed by restoration and polishing.
A stain is a colored discoloration, and can be caused by wine or oil that penetrats the surface and leaves red or a dark mark.
At Marble Maestro, we make our own recipes to remove stubborn stains on stone counters and other surfaces. And we offer a generic stain removal paste.