If you have some glass laying around and you are wondering if you can use it to fix something you need to know this. Tempered glass is glass you cant cut down. If it is tempered it will have a mark on one corner etched in the glass. Glaziers call this a bug and it lets you know do not even try to cut down. Also never set it down without putting wood or something under it because the edges of tempered glass are the most delicate and it will explode or break in thousands of little pieces.