How to distinguish the spontaneous explosion of tempered glass

First look at whether the detonation point (the cracks of the tempered glass are radial, with starting points) are in the center of the glass

For example, at the edge of the glass, it is generally because the glass has not been chamfered and edged or the glass edge is damaged, causing stress concentration and cracks to gradually develop;

If the detonation point is in the middle of the glass, see if the detonation point has two small polygons that resemble two butterfly wings (butterfly spots).

If you carefully observe that the shared edge of the two small polygons (the torso of the butterfly) should have small black particles (nickel sulfide stones) visible to the naked eye, it can be judged to be self-explosive; otherwise, it should be damaged by external force. The typical feature of glass spontaneous explosion is butterfly spots. The glass fragments are scattered radially. The center of radiation has two glass blocks shaped like butterfly wings, commonly known as "butterfly spots". The stones are located on the interface of the two "butterfly spots".