Thanks for the feedback Mel. That may explain why the original box for the QC stone is labelled " can be used with oil or water ". With regards the other honing stone; I have an vague idea these were originally marketed as Aloxite Combination Stones. I did find this early Popular Mechanics advertisement under the heading; "Sharp tools do a better job" https://books.google.com.au/books?id...0stone&f=false
Stewie;