A huge ingot of silicon - 300mm in diameter ??at the China Science and Technology Museum in Beijing, China. It was the largest silicon ingot, also known as a boule, in production at the time (2013). Ingots are formed by dipping a seed crystal into molten silicon and slowly extracting it (hence the pointed ends). Silicon is used to make microprocessor chips or integrated circuits that form the basis of all modern-day electronics.