Tempered (toughened through a process of extreme heating and rapid cooling during manufacturing process) glass is two or more times stronger than annealed glass. When broken, it shatters into many small fragments which prevent major injuries. This type of glass is intended for uses requiring superior strength and safety properties while standard glass could pose potential risk of injuries. Pencil polished: Usually the pencil polish is popular on oval and circle glass shapes. The side edge is rounded, which gives it a smooth beautiful look.