Interestingly, the main component of the earth’s crust is also silica. Silica is a combination of oxygen （O2）, the most abundant element on the earth’s surface, and silicon (Si), the second most abundant element on the earth’s surface.
Silica glass is a type of glass that can be found everywhere around us. However, unlike regular glass, which contains various other elements (metallic impurities), silica glass consists only of silica.
Silica glass has very low levels of metallic impurity, ranging from 10 ppm (1 part per 0.1 million) at the most to less than 10 ppb (1 part per 100 million) for high-purity grades.
Incidentally, “silica (quartz)” is the mineral (ore) name of “rock crystal.”
In the natural world, rock crystal is silica（SiO2）from the earth’s crust that has crystallized over many years, and appears as a colorless, transparent ore similar to diamond.
Tosoh SGM manufactures silica glass from the crystalline silica (crystal powder) contained in natural ore or from artificially produced silicide.
Rock crystal and glass are different elements, but are very closely related. The term silica glass means “glass that is made of fused quartz (crystal powder).”