Thread: Assess coticule quality?

Good question.
Different veins do exist and each vein caries a number of coticule layers, separated by Belgian Blue stone.
In the old days, raw coticule was always triaged, based on the layer it was harvested from, and even then they differentiated in purity of the stone. Some layers were considered "razor quality" while others were used for honing other tools. Even within razor hone category, there were different grades. But those were the old days. People were honing razors entirely on coticules, without going to coarser stones when more work was needed. A razor quality hone needed to be fast, very fast even, because you can't put pressure on a razor blade while honing, in the way you can push down on, let's say, a chisel, or a butchers knife. So, a lot of the gradation is about cutting speed, which is not of great importance, because nowadays, most of us use the coticule merely for polishing purposes and not for bevel restauration. I have a few different stones, and the difference in cutting speed is very obvious. You can tell something about the speed of your coticule if you observe the slurry. The slurry of fast coticules will turn grey (from the metal particles it is eating) almost instantly. Others will take many laps before you notice a little discoloration.
But they differentiated between fineness too, in the old days. I have a copy of a book that describes many different coticule layers with comments about the fineness of the hones they produce. At Ardennes Coticule (the only operational quarry) they don't sort the hones today. I think it would be very difficult to start doing that again, for the entire production, for reasons of the modern quarrying techniques they use. (dynamite as opposed to dangerous, but meticulous mining of stones 30 meters below the surface in unstable mine shafts) They have plans though, for grading at least part of the production, especially the part that's meant for razor aficionado's .
The question remains: how big are those supposed differences in fineness? From where I stand, not all that big. Perhaps even, not noteworthy big. I have access to 7 different coticules (and more to come), and there's not a single one that refused to put a good edge on a razor that required anything else to be qualified shaveready. Sure, one can still step up to Chromium Oxide, or other types of finer (and rather expensive) hones and push a razor further up the keenness ladder, but one can also shave right of any of those coticules for the rest of a lifetime and that's exactly what I'm going to do.
It's impossible to tell, without some serious double blind testing, if and which one of those 7 coticules puts the finest edge on a razor.
As it stands, I have 8 identical razors on the way, and have planned a series of comparative tests, together with a straight shaving friend. Not because I doubt the quality of certain coticules, but because it seems like an awesome and fun idea to do all kind of experiments with different honing methods and different coticules.

Nevertheless, I think you should post a picture of that coticule, just because many of us like watching them .
As for your specific problem with honing your razor, i'll put that in another post, because not every one likes to read long posts.

Bart.