The "Belgian whetstone" has been mined from the slate quarries in the Ardennes for almost 400 years now. Many tool and knife grinders will tell you that this natural stone is the very best sharpening stone you can find. It is quarried from a formation with a very homogeneous deposit of finest garnets (5-20 microns) which are the grinding particles. 35-43% percent garnets.

The composition of this around 480 million year-old soft, yellow sedimentary stone and its special sharpening qualities make it globally unique. If you rub the blade across the evenly fine-grained surface, the garnets separate from the stone. Together with the water and the rubbed off matrix of ash, clay and mica, they form a thin, very abrasive slurry. The obtuse facet edges of the garnets gently abrade the metal without gouging it. The process is fast, and it leaves the steel with a much smoother polish and a noticeably finer edge. No other stone anywhere in the world offers this combination of speed, fine finish and superior sharpness.

The Belgian whetstone is surface wetted rather than soaked. Simply put a few drops of water on the surface before sharpening.