David Weaver
...i'm not sure if there are photomicrographs of the particles or not.

I think they're not as abrasive dense as the nearly pure ark stones, and I think the claim about the abrasive shape is that they are already a bit rounded in the stone (presumably due to a natural process).

I'll have to go look at garnet hardness...as I recall, it was mohs between silica and alumina oxide. it "feels" like it's halfway between, but shape could affect that. Plus, they feel miles different just from one stone to the next, but one with enough abrasion power to feel gritty feels kind of like a dull gritty.

If I can find some substantiation, I'll post it.

Their reputation with razors (with testimonials rather than A/B tests as far as I've seen) is that sometimes a razor that will fall apart at the edge with a faster stone will still sharpen on a coticule. Even if that's the case, we would refer to that as a defective razor, and one to be thrown away given that it's possible to use a razor for an entire lifetime with an initial cost of $60. Might as well get a good one.