Silicon ingot, unknown maker, 1978-1980.
One of the many uses of silicon is as the base material for microchips. Silicon is a natural semiconductor with properties that make it good for producing tiny transistors, which are the key components of microprocessors. Microprochips hold many hundreds of transistors on a tiny piece of silicon. The silicon is purified, melted and cooled to form an ingot like this, then sliced into thin wafers ready to be turned into microchips.