Gugolz Optical Polishing Pitch comes in five grades of hardness with mixing points from 52ºC to 87ºC. The polish is ready to use without screening, filtering, or mixing additives. Made from all-natural wood resin rather than petroleum byproducts, the polish helps prevent contamination of the polishing media and substrates. Ideal use is for blocking, lapping, and polishing. The polish is also usable with CaF2, germanium, quartz, ZnSe, ZnS, silicon, to name a few.