I picked up one of those XXL stones, too. Out of the box, the stone was smooth and flat on one side, and it had a few minor surface undulations and cutting marks on the other side. A few minutes with an Atoma 120 and 400 got both sides very smooth. The edges of the stone were very sharp, so I chamfered them a bit. The two sides of the stone are almost, but not quite, parallel, maybe 1º off. (Not that this would matter.) The strata runs parallel to the cutting surface on mine. It looks and feels a lot like fine slate. I don't think it is slate though—the texture of the grain is finer than any slate I've seen. Not surprisingly, the stone doesn't absorb any water. It's splash and go all the way. So far, with that stone, I've sharpened only two Opinel Carbone knives that were quite blunt and needed a touch-up. Normally, I'd just use a 3000 stone for that, but decided to try them on this one instead. In short, my stone is hard, slow, and fine. I'd say it's in the 6000–8000 grit range. Definitely finer than my Rika 5000. Slow to raise a slurry. I helped it along a little with the Atoma 400. I got a good edge on those Opinels, but it took a fair bit longer than touching up on a Cerax 3000 or Rika 5000. The finish on the edge is not quite a mirror; it leaves a slight haze. This is a hard stone. I think it'll take me years (probably more than my remaining life span) before it will need flattening. Overall, I think this is a good finishing stone, especially at the price. It'll also work for touching up (soft-ish) steels if you are in a hurry and don't want to wait ten minutes for a soaking stone to be ready. (You'll spend a bit more time sharpening, but you'll gain more than that by not having to wait for the soaking stone to be ready.) And this stone will probably outlast three generations of sharpeners. Good value for money!