First time using tru-stone. Found it dulled chisels easy. Had to keep chisel scary sharp. I think the black is the hardest to turn. I tried a white jasper after this one and found it turned a lot easier.
I have found that any of the TruStone with the Gold web seem to be very tough on tools. Have to go slow with a sharp skew. Resharpen often. The others seem to be easier to turn and a little easier on tools. They all polish up very nicely.