Don't do it. It is poisonous. I used this stone as per the instructions and after a few hours my whole face was swollen, my eyes turned red as beets and I felt nauseous. What you don't know is that the movement of your knife on the sharpening stone creates dangerous invisible dust. I was looking at reviews of this product from another seller and another buyer had a manual geiger counter on a rock and the radiation was off the charts. I unknowingly inhaled radioactive dust. I regret using this product and I am exposing myself and my family to this product. Do not do that! I have no idea why this is being sold to consumers! This is criminal.