I have always regarded what you folks seem to call hybrids as simply poor quality coticules. I think pretty much everyone did until somebody figured out how to make extra money on them by calling them hybrids. What limited knowledge I have of the Belgian stones has always led me to believe that the cleaner the yellow tan cream of the coticule section, the better quality the stone. Nothing in my small collections of coticules has led me to think any different. Any stone imbedded in the yellow coticule HAS to be inferior just by the very nature of the coticule veins. There is no stone harvested in these mines that has superior sharpening properties to the yellow coticule and that is the way the mines priced and sold them for decades.

The 8 x 3 coticule I bought from Howard a few years back has some black streaks that appear at times as the stone wears down, but that isn't a good thing. Dark lines running through the stones are imperfections and at best do nothing but at the worst hinder getting a sharp edge as the dark stone isn't coticule but a lesser quality stone. At least this is what I believe makes the most sense and has been my experience.