When a knife's edge becomes dull, you can reset the edge with a diamond steel or ceramic steel. The difference between a diamond steel or ceramic steel and honing steel, is that a diamond steel and ceramic steel will actually grind away material from the knife, allowing it to reset the edge. The shape of a diamond sharpening steel produces an optimum edge when sharpening knives. The diamond sharpening steels have a solid stainless steel core and the surface is covered in diamond grains. Depending on the size of the sharpening steel, up to 2 million diamond grains are applied to the surface. Diamond sharpening steels have an extremely fine grit that guarantees a smooth, sharp finished edge.