Various Mines Awasedo Japanese Natural Fine Grit Sharpening Stone 1lb.5oz.(594g),
They might be Shobu or some other natural fine grit stones that are derived from Kyoto, because it came from a company that used to mine Shobu and some other quarries.
It raises great amount of black slurry quickly. It is not too soft and not too hard. It is ideal hardness. It looks that it does not need tomo nagura or the device to raise the slurry (worn Diamond lapping stone). (Scale; 1 to 10, 1-3 is very soft muddy rough grit whetstone 3-6 is soft medium grit whetstone, 6-8 is hard medium grit whetstone; 8-10 is fine grit whetstone)
It makes my blue II steel Hon kasumi blade knife Hagane became from semi-mirror finish to mirror finish, and Jigae became bright frosted silver color finish.
(Scale; 1 to 10, 1-3 give deep scratch marks to the steel, 3-5 is delete the 1-3 scratches, 5-8 makes the steel cloudy, 8-10 makes the steel semi-mirror finish or mirror finish)
Probably #6000 to #10000 grit with the same as artificial whetstone. Natural whetstone has wider capacity than artificial whetstone, and actually, we do not know until sharpen blade on the hone for a while. Because artificial whetstone molecules do not break down to smaller sizes, but Natural whetstone molecules are possible to break down to smaller sizes, and those molecules are mixed with sharpened steel molecules, and make Jigane as suitable Jigane color, and Hagane as suitable Hagane color. It is natural mystics.