I bought this stone for 1,5€ yesterday. it is so smooth like coticule but i think it is harder. i lapped it with aluminium oxide stone then i dulled my razor on glass to test it. i made milky slurry like coticule but then i made quick rolling half strokes as i read like honing with thuries. after it reached the bevel to cut arm hairs i made 50 x-strokes with the same slurry but diluted with water. it passed the HHT3 withought stropping Then i taped it and made 30 x-strokes.