Pumice polishers are generally safe to use next to most precious and synthetic stones. Great for polishing bezels and prongs that are already set.
The medium abrasive buffs out nicks and imperfections. For best results, run the polishers at 7,000–10,000rpm with very light pressure.
Knife edge wheel measures 7/8" x 1/8" (22.2x3.2mm)
Use a 3/32" screw top mandrel (#43.128)
These are the medium grit pumice wheels, made by Eve of Germany.