This is glass.
That glass could've been a block...or a chip off of it.
The main raw material in glass production—silicon dioxide, also called "silica" and best known as sand—is also a key ingredient in cement. So any bright, delicate pane of glass might have been a hard, gray cinderblock.
But that's not all. Silica is so abundant and versatile that it finds its way into all sorts of products and manufacturing processes—everything from becoming a powdered food additive to being refined into pure silicon. That means your window could have wound up in your tortilla chips or microchips.
