Whilst not a real "stone" material, it works just like the one my father had and I learned from in the 1960-s years . I saw someone write if you're over 50, that's in your youth, and he was right. I have happily used it every week since it arrived. saturate the stone; keep it moist during use; Expect to spend about five minutes on each side of the gravel on each side of the knife, yes that means twenty minutes per knife; Don't use the "corner guide" if you can't find the right angle with both hands, don't bother; Enjoy an investment in your kitchen during the pandemic.