Every time you touch your phone screen, you are holding a piece of history that almost never made it to the world. Back in the 1960s, Corning developed a super-strong glass under a secret project called “Chemcor.” It was 700 times tougher than normal glass, created through a unique chemical strengthening process. Yet, there was no commercial demand for it, so it gathered dust on the shelves for decades. Fast forward to 2005, when Steve Jobs was building the first iPhone. Frustrated with plast...