Quote Originally Posted by zib View Post
You really can't compare a Coticule, an Escher or J nat. They're different stones, and impart different edges. We don't really assign grit ratings, because they're naturals, but we guesstimate. The Coti would be the lowest, Escher in the middle, and J nat the highest (at least for the most part)

I was reading through this thread again, and saw the fingernail test. I still use it today, mostly on Coticules, If you can see the scratch, it's a soft stone, If you can't, it's hard. When you have many stones, and have seen different results, this test makes more sense. Now, with Coticules, I have always found softer ones, to be better cutters, and the harder, usually greenish to pale yellow to be better finishers. IME. YMMV.
It might just be my deceptively hard and fast stone thats strange, its a bugger to finish on compared to the la verte, oh well