100% natural "blue" sharpening stone from the Belgian Ardennes. Due to special geological play of nature, this stone contains about 30% garnet. This ensures excellent grinding properties. Size 200x50mm Grid: 4000. 533 Grams. The Ardennes-Coticule sharpening stone is a non-porous sharpening stone that should only be used with a little water. The grinding paste that is created gives an unprecedentedly beautiful grinding result.