Everyone knows how important precious metals are in jewelry making. Of course, precious metals are used to make other things, but it seems like they aren’t very prominent. For example, gold plating can be found inside electronics, palladium is used in catalytic converters for automobiles, and so on. The precious metals are important parts of these items, but you can only see them by taking the items apart. That said, there is one everyday household item that puts a precious metal front-and-center: mirrors.
In ancient times, mirrors were made of highly polished stones, like obsidian or volcanic rock. However, once refining techniques were more widespread, metal became the material of choice to create better quality mirrors using bronze, copper, tin, and other metals. Mirror-making later evolved into backing panes of glass with a reflective metal. But, the process was far from perfect. Initially, glass mirrors that could produce clear and accurate reflections were very expensive and difficult to create.
Of all the metals used in mirror making, silver has the best surface reflectivity in the visible spectrum – meaning that it makes the very best mirrors. In 1835, a German chemist named Justus von Liebig invented “silvering” – a metal refining process that is still used to make mirrors today. The silvering process deposits a thin layer of silver onto the surface of glass via a chemical reduction of silver nitrate. The layer of silver produces a flawless reflection, while the glass protects the silver from corrosion, oxidation, and scratches.
Silvering is still used to make modern day mirrors, but the process doesn’t always use silver. The glass on household mirrors can distort reflections, so aluminum is silvered onto the outside of a glass surface for precision-mirrors. Unlike silver, aluminum doesn’t need the protection of the glass, so it can be exposed to the elements and still produce clear reflections. Gold is also silvered onto infrared instruments to create mirrors that reflect infrared light without oxidizing or corroding.
But remember, the layer of metal in any mirror is very thin. Even though your household mirrors may contain silver, it’s not enough to expect a huge cash payout from a precious metal recycler.
