"diamonds are forever"
It's appealing to believe that a crystalline structure, a pretty one too, might exist until actively changed.
Diamonds are not forever. What 'blew my mind' is that diamonds are the result of compression and very slowly decompressing. That slowly over time the outer layer leaves that state and turns to dust.
Glass is a 'liquid'
I'm much less sure about glass, I'm not even sure that science is sure about glass. Apparently one process for making glass in the old days involved something blowing and spinning discs of it to produce nearly flat segments. When installed the artisan making the window would place the thicker end down for stability or some other reason. I'm not positive if glass is a liquid or not, but the reason many people might think it's a liquid is that intentional selection bias when fitting the panes of glass.
The whole concept of glass possibly being a liquid though changed the way I perceive solid, liquid, and gas states. Those labels better reflect much more temporally localized potential change and interaction than they do to uniquely describe matter.
BTW, if there is an expert, is glass actually a liquid or a solid?