Gorilla Glass is a special type of chemically strengthened material (an aluminosilicate for you material science geeks out there) that's processed in such a way as to resist scratches and other surface dings. It also withstands greater compression than standard glass, which means you have to press it (or drop it) harder to damage it.
Gorilla Glass 2 undergoes much of the same process as regular Gorilla Glass, specifically, an ion exchange that packs a protective layer of larger potassium ions at the glass' surface to create stronger compression. With Gorilla Glass 2, Corning's engineers have rearranged the order of the ions and their spacing, in order to encourage greater potassium absorption and therefore innately stronger glass.
Don’t let a simple chip in your Gorilla Glass turn into a major crack – or worse. A simple chip repair now could save you replacing the entire Screen later.