Looks similar to mine here, it should be a very nice finisher, post 8K stone. The slurry on mine looks more brownish, but you seem to have more green spots.

They are actually a pretty soft stone. I raise a thin slurry with a 1200 DMT and 2-3 drops of Smith’s Honing Solution thin the slurry to clear water and Smith. You can shave off the stone.

Equal to or better than an Escher edge.

Nice find.