High purity quartz sand is essential for lighting manufacturing. Tubes of silica glass are used in halogen lamp bulbs, which are used to envelope the high temperature tungsten filament. Halogen lamps work by using an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of a halogen gas. The halogen gas used is normally fluorine, chlorine, iodine, or bromine.
The glass used in halogen lamp must have excellent optical transmission properties and the ability to remain undamaged by extreme temperatures and thermal shock without being deformed. The tungsten filament glows at a temperature of 2500°C only a few mm away from the glass wall. Because of the high operating temperature, only high purity quartz glass can be used for this application.