Germanium is a rare, silvery-gray element that conducts electricity better than most materials but not as well as pure metals like copper. Scientists call materials with this special property semiconductors. Germanium sits right between metals that conduct electricity easily and materials like rubber that block it completely, making it incredibly useful for controlling electrical currents.

In the 1940s and 1950s, germanium revolutionized electronics. Engineers used it to build the first transistors, tiny devices that could amplify electrical signals or switch them on and off. These transistors made possible the first portable radios, early computers, and hearing aids. Before transistors, electronics relied on large, fragile vacuum tubes that generated lots of heat. A computer using vacuum tubes might fill an entire room, while transistors made from germanium could fit in your pocket.

Today, silicon has largely replaced germanium in most electronics because it's cheaper and more abundant. But germanium still appears in fiber optic cables, infrared cameras, and solar panels on spacecraft. The element has 32 protons and sits between gallium and arsenic on the periodic table.