Heres one of the most facinating supernatural occourences that I have had.
It was a glass that had been on the floor by the fence that I had set down earlier in the day. I put it right by the fence so it wouldn't get broken, it had littrally exploded into a million peices.
OK probobly not a million but it had crystalised as a car windowscreen might but much finer. Each peice of the glass that was spread out over the space of around 5m was exactly the same size, tiny cubes.
There was no one nearby who could have done it and we was nowhere near it. I strongly suspect that this had I got it on film was real prof of paranormal.
Think you will have a job with this one DB!
A few things could have happened depending on the type of glass. If the glass was cold and exploded into sharp slivers, it was probably Corelle or a similar glass. These are thin but strong. The strength comes from rapid chilling from the molten state. The surface hardens, so when the interior cools and contracts it draws the surface tightly inward. It's that tension that makes the strength, but there's a lot of residual stress--it's a tightly bound spring. If the surface is broken, that stress is released all at one and they can really explode.
If it was a heat resistant glass like Pyrex, I've heard stories that pieces manufactured years ago are more stable but newer pieces tend to shatter occasionally. Boron is added to reduce expansion which is why they're heat resistant, but these pieces tend to be thicker and if the factory used the low expansion as an excuse to cool the pieces more quickly, you'll have internal stresses similar to Corelle.
Now for the trigger. Glass accumulates scratches from normal use even if you can't see them. These scratches are weak spots, and if a scratch is at a point in the glass where there's a lot of residual stress it forms a traveling crack. The crack will follow the stress, literally unzipping that tightly bound spring that I mentioned earlier. The crack travels at several times the speed of sound and can spread outward, exploiting other weak points (scratches with stress underneath). We see it as unexpected explosive shattering.
A slight knock, tap or vibration can be all it takes to trigger the shatter.
Plain glass also accumulates surface scratches and can break with only a light tap, but it's much less likely because they aren't manufactured with stress on purpose. A crack will follow weakness in the glass and you'll get a few solid pieces. But it can happen and this is the reason you shouldn't put your hand inside a glass to wash it. Use a brush.
Certain combinations of sound or infrasound waves can also cause a glass to shatter. See link below.
I'm not sure what type of glass this was but it was one of the ones with a really thick, tough bottom part , strangley we still have a few of the original set left over from all those years and they are still in main use so not sure why one would go and not the rest.
I've checked the glasses and they are fairly scrayched up so I hope one day i'm not going to be enjoying a glass of Coke and then bang, The glass goes.
I have head of frequency shattering glass but dont remember hearing or feeling a sound like that.