Cer-Vit

Cer-Vit aka CerVit or Cervit or Cer-Vit C-101 (from 'ceramic-vitreous'), is a glass-ceramic material made up of oxides of silicon, aluminium and lithium, with ultra low coefficient of thermal expansion, used for telescope mirrors and lenses. It was made by Owens-Illinois Owens Corning in 1967, and discontinued in 1978. Cer-Vit and Zerodur are two-phase ceramics consisting of a high percentage of crystalline silica-based material and the remainder of non-crystalline glass. These ceramics also include silica-based glasses such as Homosil fused quartz, soda-lime glass, and the like.