How is gold formed?

Gold, like everything else on Earth, is believed to have been formed billions of years ago during the Big Bang. In the earliest years, stars formed of hydrogen and helium slowly burned through their fuel sources, creating heavier elements like oxygen and iron. This process - called nucleosynthesis - does not initially produce gold, but as certain stars reach the point of becoming supernovas, they can form gold particles as they explode.

The Earth is thought to have been produced by the collision of neutron stars, which are amongst the densest objects in the universe. Gold and precious metals were also formed in the course of this violent merger. Cast out by the explosive forces of neutron star collisions, the numerous elements necessary to form our planet coalesced under the influence of gravity.

During its earliest years Earth was in a molten state but, as it cooled, heavy elements – including gold – sank to the planet’s centre. Scientists therefore believe that the vast majority of the Earth's original gold remains deep within its inaccessible core.

The Crab Nebula in the constellation Taurus, 6,523 light-years from Earth. The remains of a supernova explosion are a potential source of gold.

How is gold made?

This theory about the world's formation does not explain the existence of accessible gold and silver deposits where we currently find them in the Earth's crust. Scientists believe that gold is about ten times more common on the surface than it should be. To explain how the gold we mine and use is made, there are two suggested explanations, and both involve massive asteroid impacts on the Earth.

The first suggests that asteroids, which were formed in a similar way to the Earth, crashed into our planet and deposited gold into the Earth's crust. The second theory is that the impact from massive asteroids fractured the crust and brought gold up from the Earth's core.

Both of these theories are supported by the discovery of gold near to the sites of massive ancient asteroid craters and the Earth’s fault lines.

How is gold formed in nature?

Over thousands of years, gold - along with other metals in the Earth's crust - becomes compressed and form veins. Over time, these gold veins are then eroded, placing other deposits and gold nuggets in new locations on the Earth's surface and in the seas.

Miners prospecting for gold therefore refer to either lode mining – from the original veins – or placer mining and panning – from seams of displaced gold. There are also huge quantities of gold in the sea but no economic means of extracting even an ounce of gold from the depths has been discovered just yet.