Nothing new under the sun, eh Jim? This is likely the reason why the Arkie made of pure silicate is effective. The pure silicate is "softer" on hardness scales than other abrasive material including Jnat.
Japanese steel is very close to hardness of arkie stone, but with slurries from Jnat they are transformed into powerful cutters. I have an "Arkie Kanaban." that is rust proof and pretty.