I think both Jimbo and 32t make interesting points and compelling speculation how the mechanics of garnets might work. I have to ask if there is sufficient particle( garnet) dulling really happening at modest honing pressures and short time spans engaged in that activity. Then you open up other cans of worms that only a gemologist might even understand about what it takes to break down a garnet and how much. Certainly a gem can be dulled and rounded people throw these things in rock tumblers and do it all the time but personally I feel its more about getting your blade off the rolling rocks and closer to the ones that aren't moving, those embedded in the stone surface will be doing more effective blade scratching. It may be a complicated thing or we maybe overlooking something simple.