One of those harder stones that come from the Oozuku mine it has a blue mizu coloration and a slighly foggy pattern. Very attractive. In a slightly thicker travel size at 140-52to56-17mm it will easily last a lifetime of use. The back has been roughly flattened and it sits just about one degree off from being stable. There are no inclusions or cracks, not toxic areas, but instead very homogeneous. All of my stones come with a tested tomonagura slurry stone.