Someone has asked if I can sharpen a Japanese cermic knife? Any tips? Can I?
Until someone comes up a with more intelligent answer, I'll tell you that -- I don't know. :-\
It may be harder than the grindstone, in which case, you won't be able to sharpen it. On the bright side, if you try and it truly is harder than the grindstone, you won't do any damage to either one. I would grade the grindstone very smooth and try it.