Just as a note of interest: Hard Black Arkansas Hones Are Still Used World Wide For Touching Up Dental Tools/Even Today!
I know this as a Fact as I helped a young man in India acquire one for touching up his Dental Tools. (That young man is now an Oral Surgeon) I also asked my personal Dental Hygienist what she used to keep her tools sharp and she said that while some like the translucent Arks she preferred the Hard Black.
As I said; Just a point of interest :shrug: