Quote Originally Posted by Martin103 View Post
Some naturals, after being slurried have a very distinct smell, for example the earthy smell of a coticule, the escher/thuri as well.
Touché.

While I suppose this is a feedback of sorts from the stone...is it useful or necessary, or simply an observation? (honest question, as I have not used these types of stones/hones).

In honesty, I have noted smells during grinding (even by hand on hones) that involved removal of significant (carbon) steel. I have never used this observation as any sort of guidance or feedback...just a realization, and a thought of "wow"

In the world of knives, I guess I would have to claim to have used smell as feedback. Carbon steel often has a slight "rusty" smell to it that I have used to differentiate it from stainless steels...but it only works with fairly aged or worn pieces. Hard to celebrate this too much though because there is usually an accompanying patina or bloom that can be identified on sight.