Corning Gorilla Glass

Gorilla Glass is the thin, tough glass that protects cell phones, laptop computers and millions of other portable electronic devices. Here's a look at what Gorilla Glass is and what makes it so strong.

Gorilla Glass hardness is comparable to that of sapphire, which is 9 on the Mohs scale of hardness. Regular glass is much softer, closer to a 7 on the Mohs scale. The increased hardness means you're less likely to scratch your phone or monitor from daily use or contact with other items in your pocket or purse.

The glass consists of a thin sheet of alkali-aluminosilicate. Gorilla Glass is strengthened using an ion-exchange process which forces large ions into the spaces between molecules on the glass surface. Specifically, glass is placed in a 400°C molten potassium salt bath, which forces potassium ions to replace the sodium ions originally in the glass. The larger potassium ions take up more space between the other atoms in the glass. As the glass cools, the crunched-together atoms produce a high level of compressive stress in the glass that helps protect the surface from mechanical damage.