Diamond burnishers are used to burnish/engrave anodized metals and to scratch engrave on glass. When used on anodized metals they will engrave (or burnish) the metal and bring out the ‘under shine’. These tools are not made for deep engraving. They come in tip sizes from .003″ to .030″. Larger sizes are available by special order, but can be very expensive. For jobs that require a line width larger than .030″, most engravers choose to use a carbide cutter instead of a diamond. If you are engraving on glass, you must use a diamond burnisher.