Sharpening stones among the hardest and the finest to obtain the best sharpness inside cutting edges of gouges.
Its grit is circa 8000.
4 different profiles available and a set of the 4.
It must be used with special light honing oil (e.g. 55K oil) to lubricate and prevent from clogging.
Since this stone is entirely natural, any colour variation (from white to black), line or porous area do not affect its quality in any way.