david weaver
The breaking off of material sounds a lot more like silicon carbide or something going on with wheels (are we still talking about the spyderco stones?).

What happens with spydercos is actually very similar to natural stones, though with a harder abrasive than all except 15-20% of what's in japanese natural stones (aluminum oxide from settled volcanic ash).

I regard them as being similar to oilstones in that unless you're abrading the surface fairly often, they will become fairly slow (in my mind, a good thing on a fine stone if you're sharpening freehand). If they're abraded, just like an oilstone, they will cut many multiples as fast and raise a wire edge.

They present with a feel of a dulling surface rather than one getting finer with fractured particles.

Not sure who makes the stones for them, but it was coorstek before, so I wouldn't trust any of their advertising about process - it may be someone else's process with little incentive to really get the description right.

they do make a 1/4" thick 8x3 ultra fine stone that is a real bear to get flat if it's not perfectly dead flat when new -FAR harder to get flat than any natural oilstone. I always wondered how guide users get along with a stone like that as guide use sort of dictates the need for a faster finish stone due to the inability to bias angles.