It can be distinguished from the state of the fragments formed by the fragmentation of a piece of glass: the formation of relatively small pieces of regularity is the general tempered glass; most of them are regular small pieces, and a small part of the central area is a relatively large piece, that is, the area of tempered glass In addition, it is not tempered glass. This method of identification is simple, but it has to destroy the glass, can it not break the glass? Also. Tempered architectural glass and household glass are heat treated to be tempered, so they all have stress lines left by heat treatment, and the stress lines are usually invisible.