La pierre de Vielsalm, the Coticule is a natural whetstone with a rich history. The mining and production of the Coticule in the Belgian Ardennes dates back to the 17th century. It is a sedimentary rock formed over 480 million years consisting of greyish-yellow volcanic ash and clay containing hard garnets. These Spessartite Garnets were formed by a rearrangement of minerals under the influence of a regional metamorphism. Due to the capriciousness of nature, the Coticule occurs only in thin vertical layers, enclosed between broad layers of blue-purple shales. As a result, its mining has to be done very minutely and mainly without the interference of machinery. This mining is a very time-consuming, labour-intensive and costly work that can only take place for a few months a year under the influence of all kinds of weather conditions. Production is 100% artisanal and makes each stone a unique specimen.

The Belgian grindstone is composed of 30 to 42% garnets bound together by Mica. It is to these garnets that the Coticule owes its exceptional grinding properties. The geometric shape of this garnet is a dodecahedron. These are twelve planes connected together with obtuse angles. The garnets have a diameter of 5 to 15 microns and penetrate 1 to 3 microns into the metal to be ground. This ideal geometric shape ( obtuse angles polish the metal) and the numerous presence of these garnets ensure very fast and extremely fine grinding at the same time. This results in a razor-sharp cut in just a few minutes, and this for any object to be sharpened.

The Belgian whetstone is quickly compared to a 4000 - 8000 grit whetstone, compared to the Japanese grit system, but one should bear in mind that it is a natural product, so no stone is 100% identical. The grit designation serves purely as an indication and says little about the specific properties of the stone. The advantage over other whetstones is: the Belgian whetstone sharpens very finely and very quickly. No other whetstone possesses this combination.

Because of their hardness, the garnets are capable of sharpening any type of steel including stainless steel ( Inox 18/8 and 18/10, among others), Damascus Steel and HSS High Speed Steel. The geometric shape of the garnets gives another unique feature to the whetstone. Due to their flattened shape, the garnets polish the metal without leaving tiny burrs behind. This results in a fine shine without scratches on the cut which significantly increases comfort during use.