I recently purchased a 6 x 2 inch Coticule and slurry stone. When I develop a slurry and attempt to hone a razor the swarf doesn't seem to darken very much compared to all the videos I've seen on Utube. However the small bout that I purchased as a slurry stone responds much faster and darkens quicker when I stroke a knife across it. I've done it on the larger stone with a knife as well,but the small stone is quicker. Could the larger coticule be too slow a cutter because I'm haveing difficulty using it to hone my razors. Or is is "the nature of the beast" I've tried a couple of different methods to hone with it mostly out of curiosity. When I run a small pocket knife that is very sharp across the smaller stone it leaves black marks on the stone whereas the larger one doesn't seem to make those marks.....