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frictionites are barber hone size, since that is what they are, and have two distinct sides. The colors blend a bit where they join but no resemblance to sedimentary layers.

I'm not a coticule expert but I've fooled with a fair amount of them over the years. AFAIK they originate in Belgium. If I'm not mistaken there was a vein of coticule that ran into Germany and those...