Welcome, Deerleg. Soapstone and carbon black. Your grandfather worked during a period when quality mattered...rather than production numbers. Kelly(GT) once had a motto of "Quality 1st or Scrap"...they made no blems...if something was wrong cosmetically with a tire they sliced it. They scrapped that mentality years ago now...and both GT and Kelly have suffered. Sounds like you have some fond memories of your grandfather. Study it over, you'll have to decide whether you want the responsibility...a lot has changed in beekeeping since your grandfather's days in it.