Answer: Silicon

The case may be ceramic, the connectors may be gold or other metals, but the bulk (and heart) of modern microchips is the natural semi-conductor silicon. From the smallest on-board chip to the biggest and beefiest cutting-edge CPU, that heart is a bundle of tiny transistors etched into layers of silicon. While the raw material inside microchips has remained largely unchanged over the last forty years, the technology behind chip construction and transistor etching has evolved radically.

From the 1970s to the present, ever increasing miniaturization has led to increasingly powerful processors. In 1971, Intel released the Intel 4004 processor, which sported a scant 2,300 transistors. By comparison, Intel’s six-core Core i7 Xeon processor—seen in microscopic close-up above and released forty years later in 2011—sports a staggering 2,270,000,000 transistors—nearly one million times more than their original processor.