You can tell the type of glass by the way it breaks

Different types of glass break in different ways. Float Glass when it breaks forms sharp, razor like shards that are very dangerous. Laminated safety glass, which is float glass joined together by a laminated interlayer, stays together when broken and forms a spider web effect. Toughed Safety Glass, which is Float Glass that has undergone a heat treatment to make it 5 times stronger than ordinary glass, forms small rounded granules when it breaks that won’t cut a person.

Read more about Jim’s Safety Glass