A line of optical lapping pitch offered in five grades for polishing CaF2, germanium, quartz, ZnSe, ZnS, silicon and other materials is available from Meller Optics, Inc. of Providence, Rhode Island. Gugolz Optical Polishing Pitch is made from all-natural wood resin, rather than petroleum byproducts, and comes in five grades from very-soft to very-hard with…