Glassblowing

Glass blowing has been around for a very long time, but the techniques of glassblowing haven't advanced much. There's been new technology to help, but the overall technique is pretty much the same. Glass is an amorphous solid, or a no crystalline solid. The molecular structure is more like a liquid's, it's randomized,  which is why it's transparent. In glassblowing, they use top quality sand. Regular sand from the beach has too many impurities. Sometimes they add stuff like alumina, magnesia, boron oxide and lead oxide to make it easier to blow the glass. A common type of glass used is soda lime glass. It's 72% silica, 15% soda (sodium dioxide), and 9% lime (calcium oxide). Those materials are fluxes. They lower the melting point and decrease the viscosity of the glass while it's melted. It also makes it stronger. If you add different metal oxides, it will add a color. If you put cobalt in it, it will make it blue.

Pic creds

Article