Silicon Crystal

The photo shows two silvery pieces with a crinkled, shiny surface, as if someone wrapped a stone in aluminium foil and forgot to unwrap it. This is silicon. And it is worth saying right at the start: it is not a mineral mined from the ground. According to Wikipedia, silicon very rarely occurs in its pure form in nature. These pieces were made by people.

Which is funny, because silicon is everywhere. According to Wikipedia, it is the second most abundant element in the Earth's crust, about 28% by mass, after oxygen. More than 90% of the crust is made of silicate minerals. The quartz, amethyst, jasper, moonstone and tourmaline on this site all contain silicon. It is just that in nature it is always bound to oxygen. Getting it on its own takes hard work.

How is it done? According to Wikipedia, quartz or sand is heated with coke in an electric arc furnace, which gives silicon of 96 to 99% purity. For electronics and chips that is still not enough, so it is purified further. The common method, the "Siemens process", produces rods of polysilicon that are broken into chunks. According to Wikipedia, polysilicon is made of many small crystals, which gives it a "metal flake effect". The crinkled surface in the photo looks exactly like that, but we have not checked which process our stones came from.

The name has a story too. According to Wikipedia, in 1808 the English chemist Humphry Davy proposed the name silicium, from the Latin silex, flint. In 1817 the Scottish chemist Thomas Thomson changed it to silicon, because he believed it was not a metal. The Hebrew name, tzoran, comes from exactly the same place: tzor, flint. By the way, silicon is not the silicone of baking molds and sealants. That is a family of materials made from silicon.

And what do you do with silicon besides putting it on a shelf? According to Wikipedia, it is why our era is called "the Silicon Age": it is the basis of transistors, chips and solar cells. It gave its name to Silicon Valley in California, and to Silicon Wadi in Israel. So the device you are reading this on may well be made of the same stuff as the stone in the photo.