Genuine, natural Arkansas stones are the only stones in the world that polish your cutting edges as they sharpen. This stone offers a different grade on each side; one side is a soft (medium density) Arkansas stone, the other is a Dunston black (extra-fine density) Arkansas stone. The soft grade is the coarsest of the Arkansas stones, ideal for the first steps in sharpening, for creating the initial edge. The Dunston black (dark-gray in color) is harder and finer for achieving a fine, polished edge. Arkansas stones are great for use on gravers, knives and other cutting tools.