Gold has many uses in the production of glass. The most basic use in glassmaking is that of a pigment. A small amount of gold, if suspended in the glass when it is annealed, will produce a rich ruby color.

Gold is also used when making specialty glass for climate-controlled buildings and cases. A small amount of gold dispersed within the glass or coated onto the glass surface will reflect solar radiation outward, helping the buildings stay cool in the summer, and reflect internal heat inward, helping them stay warm in winter.

The visor on the helmet of an astronaut’s space suit is coated with a very thin film of gold. This thin film reflects much of the very intense solar radiation of space, protecting the astronaut’s eyes and skin.