All you people calling the OP a fraud need to chill the f*@# out. The glass that's used in these devices is chemically tempered glass. (This includes Gorilla Glass.) In order to make it stronger, a finished piece of alkali glass is bathed in molten potassium salts, so that smaller sodium ions in the glass get replaced by larger potassium ions. This places the surface of the glass under a large amount of compressive stress. Get it? It's under stress. The only reason why it doesn't break spontaeously is because the stress field is set up in equal and opposite directions. Any tiny microscopic flaw in the glass can result in propagating cracks. Also, the glass can be over tempered, resulting in too much stress, making the glass more vulnerable to this kind of thing. So the situation that the OP described is quite feasible.
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