Could this be a synthesized version of a coticule. I seem to recall an old thread on here about just such a mystery stone and a prevailing theory was that at some point a coticule quarry saved its leavings and bound it together somehow into a hone. So pretty much just like today's modern synthetic hones only using coticule slurry as its matrix? I am curious but I find this theory to be very possible. I have one of these stones myself. They are aggressive and make good pre-finishers but IMHO they lack the finesse and subtlety of a real natural belgian hone. .....JM2¢