We use different glass for different watch styles, but all glass used is scratch-resistant and very durable.
The Classic, Barrel, and Minimalist use mineral crystal. Mineral crystal is an ordinary glass crystal that has been heat treated or chemically treated to withstand scratches.
The Chrono, the MLB Collection, and all Automatic watches use sapphire glass. Sapphire glass is a synthetically produced crystal second only to diamond in its hardness, making it extremely durable.