http://home.fotocommunity.de/mike.a.wilson/index.php?id=529253&d=2639601
Not easy to see at the scale presented but this piece of glass has been produced so that it gradually cracks and disintegrates. You can see some of the breaks starting.
mike
http://home.fotocommunity.de/mike.a.wilson/index.php?id=529253&d=2639601
mike