Silicon dioxide SiO2, when derived from the melting of sand or rock, is generally called fused quartz. The synthetic version is called fused silica. Silicon dioxide is commonly used in the production of optical glass, electrons, and semiconductors.
As an optical material, silicon dioxide is a strong material with good levels of resistance to thermal shock, chemicals, and scratching. Its a good material to use for windows and its low thermal expansion makes it a good candidate for mirrors. May also be found in: polarizing optics,
lenses, prisms, and laser components.