| I've looked at clouds... |
In the early 1800s, crown glass was made when glassblowers blew a large sphere or bubble of glass and spun it until it was a flat disk. They could then cut it into panes, but there was always bump or "crown" in the middle. Around 1825, glassblowers made cylinders instead of bubbles, and when cooled, they were sliced down the side so they could be opened up into flat sheets.
| from both sides now... |
So is glass a solid or liquid? Mineral or not? These are age-old questions.
It's not a mineral. It has no crystalline structure, which is one of the requirements for mineral-hood. But solid or liquid? It sure feels solid when you run into it, but doesn't it look like it drips and droops over time? How can a solid do that?
Glass is called an amorphous solid, which means it doesn't have a crystal structure, but it's not a liquid. The reason old glass is so warped and warbly apparently is related to what I described above - the old method of pouring or blowing glass. The glass never came out completely smooth, and the warps and warbles stay in the glass once cooled. So the beautiful reflections of the church windows are there to stay forever, unless some unappreciative person removes them to replace them with something else. Not us! We appreciate them!