Some years ago when I lived in Nebraska, I used to go up in the Black Hills of South Dakota and pan for gold. I'd find some gold, but in some areas there were lots and lots of garnets in the bottom of my green plastic gold pan, along with the normal "black sand". The garnets are heavier than most dirt and rock pieces and would naturally end up in the bottom of the pan. I've seen them from the range of sizes of little reddish brown speck about like this period -> . to some up around the size of this smiley -> :) Digging out the magnifying glass they were always kind of funny rounded objects with facets. Over around Keystone and some of that area you could find pieces of river rock that had garnets protruding right out of the rock that you could really see. Some like small diamonds, much larger than what one would normally find in the pan. So, with the Coticule, I would think they are a mixture of pieces like this in the "clay" part of the rock. Sedimentary, but with the layers of fine micron and sub-micron particles composing the main rock. But, if they were sedimentary and deposited as tiny worn down pieces of an original crystal, it would make sense that they no longer held their same shape they once had. Perhaps crushed by larger rocks and ground a bit, the abrasive waxed strong in the rock and had the ability to abrade steel.
Glen has often said, and he is right, that there is more to the hone than the abrasive. There is the filler and the binders as well. All of this contributed to the work and working of a hone be it man made of one made by God, and hewn out of the earth by man. I would like to think that the Coticule has some of the intact crystals that relegate themselves to the microscope that are not crushed beyond recognition. Perhaps they do exist. I've not seen a SEM image of the surface of a Coticule. And, they are as different as individual snow flakes, yet snow is snow.
