paul womack
> In order for a stone to effectively sharpen at all, the distribution of particle sizes has to be pretty narrow. It only takes a few outliers from the previous stones grit range and you'll never remove all of the coarser scratches (since you'll constantly generate new ones).

That appears unarguable - which leaves a mystery, assuming that the reports of good sharpening performance with (assumed ;-) non uniform natural stones are validated.

BugBear