Gorilla Glass is a special type of chemically strengthened material (an aluminosilicate for you material science It also withstands greater compression than standard glass, which means you have to press it (or drop it) harder to damage it. Sourced from:

So how does it all work? The first process of making gorilla glass starts with fusion.

This simple process helps to keep the product very pure (regular float glass has a layer of tin oxide on one side). Sourced from:

Apple iphone 6s/iPhone 6* (iOS) Apple iphone 6s Pus/iPhone 6 Plus* (iOS) Asus ZenFone Sony Xperia C3 dual Google Nexus 5 Google Nexus 6 (2014) Google Nexus 5X (2015) Google Nexus 6P (2015) HTC One (M8) HTC One (M9) HTC One Mini HTC Sensation HTC Thunderbolt Sourced from: