Gold,forged in the cosmos from colliding neutron stars,is among Earth’s rarest elements.But how much of this precious metal exists, and how much remains undiscovered?
How Much Gold Have We Mined?
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The U.S. Geological Survey (USGS) estimates that humans have mined approximately 206,000 tons (187,000 metric tons) of gold throughout history. Much of this gold is used in jewellery production.
The World Gold Council‘s estimate is higher, stating that 238,391 tons (216,265 metric tons) have been mined. This amount would form a cube about 72 feet (22 meters) on each side. According to the council, 45% of this gold is in jewelry, 22% is in gold bars and coins, and 17% is held by central banks.
Remaining Gold Reserves
While a significant amount of gold has been mined, significant reserves remain. The USGS reports roughly 70,550 tons (64,000 metric tons) of gold in economically viable deposits worldwide. Russia, Australia, and South africa hold the largest untapped reserves, while China led in gold extraction in 2024.
Reserves refer to economically extractable portions of ore deposits, while resources are less certain ore deposits.The World Gold Council, using data from Metals Focus, estimates global gold reserves at 60,370 tons (54,770 metric tons) and resources at about 145,626 tons (132,110 metric tons).
Related: Why is gold so soft?
Combining USGS and world Gold Council estimates, there are approximately 277,000 to 299,000 tons (251,000 to 271,000 metric tons) of gold in human objects and known crustal deposits. However, this figure remains uncertain.
Gold Throughout Earth’s Crust
Most of Earth’s gold exists as tiny, uneconomical particles throughout the crust, particularly in seawater and igneous rocks, according to the University of California, Berkeley. The crust’s gold concentration is about 4 parts per billion, or 0.004 grams per metric ton. The Royal Mint estimates that the total weight of these particles is around 441 million tons (400 million metric tons).
However, this is a small fraction of the gold within the planet. Geologists believe that 99% of the world’s gold is locked in Earth’s core, enough to coat the planet in a 1.6 feet (0.5 m) thick layer.
Why is Gold in the Core?
During Earth’s formation, most gold sank into the core due to its density, according to Chris Voisey, an ore deposit geologist and research fellow at Monash university in Australia.
Voisey explained that 99.5% of Earth’s mass was molten, allowing gold to sink to the core based on density. The remaining 0.5% arrived later during the “Late Heavy Bombardment,” a period of intense meteorite impacts between 4.1 billion and 3.8 billion years ago. This 0.5% contains the gold found in rocks and ore deposits today.
This gold did not sink into the core because Earth had already formed a solid crust.Voisey noted that many of Earth’s precious metal ore deposits are believed to originate from this event.
Gold Delivery Via Meteorites
Since the Late Heavy Bombardment,gold input from space has been minimal. Voisey stated that meteorite deliveries of gold are “more or less negligible,” and existing gold is simply redistributed by geological processes to form ore deposits.
Voisey “seriously doubts” that researchers could ever accurately measure all the gold on the planet, given the vast amount in the core and variable concentrations in the crust. He added that it would be “unfeasible” to determine how much gold remains undiscovered.
