Screen protection

[Mark Zuckerberg]

As touchscreen displays are growing larger in recent years, the need for enhanced scratch resistance and protection of the screens created the demand for usage of screen covers of increased resistance including chemically hardened glass.
Cornings Gorilla Glass is a popular brand of hardened glass used for high-end handset in the mobile industry.
Additionally, manufacturers has started applying oleophobic coating on top of its screens to make finger smudges less of an issue.