There's Enough Gold in Earth's Core to Coat the Entire Surface

During Earth's fiery formation, our planet was a turbulent, molten sphere. In this chaotic environment, a process called planetary differentiation took place. Heavier elements, under the immense pull of gravity, began to sink toward the planet's center. Iron, being both abundant and very dense, made this journey in vast quantities to form the core. As it did, it dragged other dense, "iron-loving" (siderophile) elements along with it, including an incredible amount of gold. The vast majority of our planet's original precious metals were effectively locked away thousands of miles beneath our feet.

This geological process explains why gold is so rare in the Earth's crust, but it also raises a question: if all the gold sank, where did the deposits we mine today come from? The leading theory is that this accessible gold is extraterrestrial in origin. After the core had formed and the planet's surface began to solidify, Earth was pummeled by a bombardment of asteroids and comets. This "late veneer" of cosmic debris delivered a new supply of precious metals, seeding the crust with the gold that civilizations have cherished throughout history.