Toughened or tempered glass is used most often for applications that require elements of strength and safety. The most common use for this glass in residential is in shower screens and for shopfront doors entrances in commercial projects. Toughened glass is made up from ordinary glass and then put in a furnace to re-arrange its molecular structure to strengthen it. Much like the blacksmith methods used for making steel swords and weapons, the heating and quenching effect produces a strong molecular bond. Toughened glass breaks into many small pieces when broken and usually never cracks.