The glass, a microalloy made of palladium, has a chemical structure that counteracts the inherent brittleness of glass but maintains its strength. It’s not very dense and it is more lightweight than steel, with comparable heft to an aluminum or titanium alloy. “It has probably the best combination of strength and toughness that has ever been achieved,” said Robert O. Ritchie, a materials scientist at Lawrence Berkeley National Laboratory who is one of the authors of a paper describing the new glass. “It’s not the strongest material ever made, but it’s certainly one of the best with a combination of strength and toughness.”