Gold

Gold is a soft, heavy, yellow metal that never rusts or tarnishes, which is why people have prized it since prehistoric times. It is found as nuggets and specks in rock and riverbeds, and is mined worldwide, with China, Australia and Russia among the top producers.

Those same qualities make it valuable in electronics, where reliable contacts matter more than cost:

• Bond wire: gold is so easy to stretch that it can be drawn into wire thinner than a hair, linking a chip to its package.
• Connector: a thin plating where contacts touch keeps them conducting for years.
• Display driver chip: tiny gold bumps connect the chip to the flexible printed circuit that feeds the screen.