Hardness of coticule based on slurry color
I've read on this forum before that the slurry used on most coticules will darken after some number of passes.
I recently tried to remove scratches left by a 1k diamond plate by working the razor on the coticule with slurry in a circular fashion using reasonable pressure (way more than one would use when trying to get a sharp edge). For the first time, I noticed the slurry darken a bit after a 1/2 minute or so of circles. I have never seen the slurry change color when honing using normal, light pressure before.
Does this indicate that my coticule is on the harder end of the spectrum? It is currently the next stone I use to remove diamond plate scratches, but I am wondering if it is too hard for that purpose. Thanks for your thoughts.