Macor is the trademark for a machineable glass-ceramic developed and sold by Corning Inc.

Holand, Wolfram and Beall, George H. Glass-Ceramic Technology.

Zerodur, a registered trademark of Schott Glass Technologies, is a lithium aluminosilicate glass-ceramic produced by Schott AG since 1968.

From circular "blanks" of a special glass-ceramic developed in West Germany, the hexagonal mirror segments - each weighing about 1,000 pounds - are being fabricated by Itek Optical Systems in Lexington, Mass.