8.2 metre blank for VLT One of the most enduring brands of glass ceramic is Zerodur from Schott AG, headquartered in Mainz, Germany. Glass–ceramics are ceramic materials produced through controlled crystallisation (nucleation and crystal growth) of a parent glass. The great variety of compositions and the possibility of developing special microstructures with specific technological properties have allowed glass–ceramic materials to be used in a wide range of applications. photonics books: The Properties of Optical Glass (Schott Series on Glass and Glass Ceramics) - Hans Bach Glass-Ceramic Technology 3rd Edition - Wolfram Holand, George H. Beall techbriefs Robax Ceran