Super-hard transparent ceramic looks good

One of the hardest materials known – silicon nitride – has been turned transparent for the first time. The see through ceramic could be used for ultra-tough windows able to withstand extreme conditions. Norimasa Nishiyama, from the German Electron Synchrotron DESY, and an international group of researchers from Germany and Japan have now created a disc of transparent silicon nitride 2mm in diameter. The ultra-hard but cheap material can withstand temperatures up to 1400°C.