Born from explosions of distant stars and largely trapped in the glowing heart of our planet, gold intrigues as much as it fascinates. Its apparent rarity, however, is only a reflection of our ability to achieve it. If the jewelry and ingots we know represent only a tiny portion of the real amount of gold on earth, geologists continue to track down this elusive metal, hidden in the depths or disseminated in the earth's crust.
But it was only after an episode known as “late bombardment”, between 4.1 and 3.8 billion years, that the earthly surface received new gold inputs by meteorite impacts. This last percentage, very thin on a planetary scale, is the one that humanity exploits today.
The history of gold extraction begins with ancient civilizations, but it was from the Californian gold rush in 1848 that world production experienced a spectacular leap. The World Gold Council estimates that two thirds of all the gold ever extracted have been produced since 1950, in particular thanks to the progress of mining techniques and the discovery of new deposits.
What we really know about the amount of gold on earth
Precisely evaluating the total quantity of gold on our planet is a scientific challenge. According to US Geological Survey, around 206,000 tonnes of gold have been extracted since the start of humanity. The World Gold Council, for its part, advances a slightly higher figure, estimating this total at 216,265 tonnes at the end of 2024.
But this is only a tiny fraction of theoretical stock. The Royal Mint estimates that a ton of rock contains an average of 4 milligrams of gold. This would correspond to around 400 million tonnes, distributed throughout the earth's crust. This gold is too dispersed to be exploited with current means.
The terrestrial nucleus would contain more than 99% of all the gold on the planet. This metal, attracted to the center of the globe during its formation, would be stored there in quantities as it would cover the terrestrial surface with a layer more than 40 centimeters thick. This dizzying estimate underlines how much the gold portion really available on the surface is minimal.
A rare resource, but far from being exhausted
Gold keeps a part of mystery, even after centuries of exploitation. According to the USGS Mineral Commodity Summaries, nearly 64,000 tonnes remain accessible. These deposits are considered profitable with current means. The largest are located in Russia, Australia and South Africa. However, China retains first place among world producers.
Experts make a clear distinction between two concepts. The reservations designate the profitable deposits to be exploited today. Resources are less known or difficult to exploit for the moment. Together, they would represent more than 132,000 tonnes of gold worldwide.
In addition to the gold already extracted, known reserves and resources could represent an additional 196,000 tonnes. This corresponds to the gold that could be technically exploited with the current means. Even if this quantity remains much lower than that hidden in the terrestrial nucleus, it remains considerable. It shows that the gold available on the surface is still far from exhausted.
The idea that humanity can one day lack gold therefore seems premature. But extracting this metal remains an expensive company, energy -consuming and often destructive for the environment.
