Hey, Couple of weeks ago it saw a C Nat on Amazon here in the UK. Claimed to be 10k. Thought I would give it a go at £6.99, I had to get some other stuff to qualify for free postage but I needed a few things anyway. Turned up a few days later, I made a slurry stone for it and got started. Pretty slow to begin with but improved after a short while. I finished up and I had a pretty darn good edge on Aogami #2 and Shirogami #2. I was impressed, not used a C Nat before so I have nothing to compare it to as such but the 10k claim did not seem unreasonable and the edge was sickly sharp. The stone is now performing better each time. I posted this for those folks that are curious about natural stones and may want to have a go at a good price. The stone I received was very flat and well finished and you get an anti slip mat and a small spray bottle in the box. Some sort of slate from the usual mythical place but who cares, it worked for me and didn't break the bank. Worth a punt?