Pumice Wheels

Test your pumice wheels and other abrasive wheels on a piece of glass.  If they do not abrade the glass, they will not scratch most faceted colored stones, and would be safe to use cleaning up the prongs.  Glass is around 5 ½ on the Mohs scale, which is softer than most faceted colored stones.  Although these wheels will not scratch harder gemstones, you still must use caution as the wheel may chip the facet lines of fragile stones.

Brad