With high quality quartz sand as the main material. Add the trimmings properly. Due to their high refractive index, low dispersion and good chemical stability, rare earths can be used to produce optical glass for advanced cameras, video cameras, telescopes and other advanced optical instruments. For example, lanthanum glass with excellent optical properties containing lao360% and b2O340 % of boron oxide is an indispensable optical material in the manufacture of advanced camera lenses and periscope lenses. In addition, some rare earth elements can be used to produce radiation-proof glass.