I have been engraving glass the Old World style for 35 years. I apprenticed with a master glass engraver who cut for Fostoria Glass. I shape stone wheels made out of carborundum, a stone that is second hardest to diamond.
Each shape on the wheels do different cuts depending on the angle and pressure that I apply. Sadly, this craft has become lost to time. There are only a couple of hundred in the US still engraving glass. I am the only one in Michigan.