GThe yellow precious metal has been part of human history for millennia and remains the most cherished precious metal still today.
Its allure lies in its extravagant color, malleability, and resistance to environmental exposure. As one of the first metals ever worked by humans, gold continues to hold a special place in our history and culture. Its enduring popularity inspires many questions, particularly regarding its formation.
This article will explain the complex process that answers the question "how is gold formed?" that involves supernovas and geological activities that started over a billion years ago.
Source, The Metropolitan Museum of Art.
KEY TAKEAWAYS
- Gold is formed in supernova explosions or neutron star collisions through the rapid neutron-capture process (r-process);
- On Earth, gold is transported from deep within the planet to accessible deposits via geological processes over billions of years, including hydrothermal activity, erosion, earthquakes, volcanic eruptions, and events like asteroids hitting the planet;
- Extraction techniques have evolved from historical methods like mercury amalgamation to modern processes such as cyanidation;
- Gold is used extensively in jewelry, electronics, medical applications, and aerospace due to its unique properties;
- Nowadays, gold bullion is a popular form of investment. It is considered a safe haven asset that helps diversify an investment portfolio and protect wealth in the long run.
Please continue reading to explore the process of gold formation, the methods used to extract it, as well as its various industrial, commercial, and investment applications.
How Is Gold Formed on Earth: Geological Processes
First off, we need to understand that there are two forms of gold ores: exogenetic and endogenetic.
Exogenetic gold, such as alluvial gold, is found at the Earth's surface, while endogenetic gold is accessed within the Earth.
Endogenetic gold ores include gold veins and lode deposits of elemental gold in quartzite or mixtures of quartzite and iron sulfide minerals like pyrite and pyrrhotite.
Throughout Earth's history, hot fluids circulated through gold-bearing rocks, forming veins or lodes by carrying off gold due to its weight and chemical properties. In other instances, gold nuggets and flakes were carried away by water currents.
Gold atoms in rock ores can appear as flakes, pure native elements, or in the natural alloy electrum with silver.
Erosion releases gold from other minerals, allowing it to accumulate in stream beds, alluvial deposits, and the ocean. Scientists believe there is still eight times more gold in and under the oceans than has ever been mined near the planet's crust.
Earthquakes and volcanic eruptions also play a role in forming gold deposits. Shifting faults caused by earthquakes rapidly decompress mineral-rich water, which vaporizes and deposits quartz veins and gold onto rock surfaces.
Now that you have learned that gold is not necessarily created on Earth, but it does occur naturally, keep reading to learn more about how one of the most common periodic table elements, gold, is formed.
The Origin of Gold
The gold's journey began even before our planet's history.
The most accepted theory about the origin of gold starts in distant outer space. Remember when Carl Sagan said, "We're made of star stuff"? So also is gold.
Gold can only be produced under immense energy conditions found in the explosion of two neutron stars, and the collision between these massive stars ejects a gamma-ray burst. These extreme environments produce enough energy for heavy elements to be created through the rapid neutron-capture process, known as the r-process.
Then, how did this precious metal arrive on our planet? Well, while the earth was forming, it was a cauldron of molten rock. Heavy elements, such as gold, precipitated towards the earth's core. Yes, there is an immense amount of gold still in the earth's molten core.
However, billions of years ago, because of many asteroid impacts, much of the gold formed was forced into the mantle and the earth's crust, sometimes at placer deposits, making finding gold relatively easy for humans. But this does not mean it is inexhaustible.
Unfortunately, gold cannot be produced via chemistry or alchemy. Chemical reactions cannot change the number of protons within an atom. (The atomic number of gold is 79, which means there are 79 protons in the nucleus of every atom of gold.)
Even though it can be formed by the nuclear processes of fusion, fission, and radioactive decay, this process is very expensive, sadly, so it is more economically feasible to mine it.
Gold Deposits
Now that you know the origin of gold and its arrival on Earth during its early formation, let's now examine where these gold deposits are currently located and who holds the world's largest reserves.
According to Statista, Australia and Russia hold a large share of the world’s gold mine reserves in comparison to other countries, accounting for 12,000 metric tons and 11,100 metric tons, respectively, in 2023. Global reserves amounted to 59,000 metric tons that year.
Statista's records from the fourth quarter of 2023 also show that the United States Central Bank held approximately 8,133.5 metric tons of gold at that time.
Have you ever wondered how much gold there is in the world? All the gold discovered thus far would fit in a cube that is 23 meters wide on every side. Interestingly, gold can be found on all of Earth's continents except Antarctica, and even that continent might have some of it undiscovered underneath the ice.
Gold Extraction and Refining
Having discussed the largest mine reserves in the world, let us now delve into the extraction and refining processes.
Exploration
Gold exploration begins by determining whether gold can be found in the ground, either at a new site or an existing resource. Geologists conduct detailed structural mapping, sampling, and geophysics to identify target areas.
If potential gold mineralization is found, initial drilling begins, involving drilling holes, logging rocks, and taking samples to determine the size and grade of a potential deposit. If successful, further drilling defines the resource, which engineers then assess for economic viability.
Mining
There are two types of gold mining: open-cut and underground.
Open-cut mining, used for deposits close to the surface, involves removing waste rock to access the ore. Giant shovels and trucks transport the gold ore to crushers.
Underground mining is used for deeper deposits, involving vertical shafts and tunnels to access and haul ore to the surface. Extensions of open pit deposits may also be mined underground.
Gold is not always in pure form, so the refining process is the next step.
Amalgamation
Mercury was used by ancient Romans to mine gold and silver because it dissolves both metals. When gold is mixed with mercury, it forms an alloy called amalgam. To further separate mercury from gold, the amalgam is heated inside a sealed retort recipient to distill off the mercury, which is recovered for reuse.
The widespread use of mercury in mining ceased in the 1960s. Although the effects of mercury use are well known nowadays, it is still used indiscriminately in clandestine and private mines.
Cyanidation
The cyanide process extracts silver and gold from their ores by dissolving them in a dilute solution of sodium cyanide or potassium cyanide.
The method consists of three steps: first, the finely ground ore is contacted with the cyanide solution; second, the solids are separated from the clear solution; and third, the precious metals are recovered from the solution by precipitation using zinc dust.
Industrial and Commercial Uses of Gold
Because of desirable combinations of physical and chemical properties, this yellow metal also emerged in the late 20th century as an essential industrial metal thanks to its metallurgical properties, high conductivity, and malleability.
The majority of gold is used in jewelry in various alloys, including to form white gold, which displays wealth and status. Gold's malleability and resistance to tarnish make it ideal for crafting intricate designs or stretching it even to a gold leaf.
Thanks to its high electric conductivity, malleability, and resistance to corrosion and oxidation, gold is widely used in many electronic devices.
Gold's biocompatibility makes it valuable in the medical field. It is used in dentistry, hearing aids, and even acupuncture needles, helping to prevent allergic reactions.
Because it reflects up to 98 percent of infrared radiation, gold has infinite applications in the defense and aerospace industries. It is used in the windshields of jets, the visors of astronauts’ helmets, satellites, and other space vehicles.
Read more on our article about the Top 10 Uses for Gold.
Gold as an Investment Vehicle
Because of its intrinsic value, gold, like other precious metals, has been used as an investment option as a safe-haven asset against inflation and the devaluation of fiat currencies.
On May 20, 2024, the metal traded at the historical $2,450.05 per troy ounce, which is gold's highest price ever recorded. This can be explained by the trust people have in gold during current sensible geopolitical events.
Gold bullion primarily consists of gold bars or coins of at least .995 fineness. It is produced mainly for investment purposes.
Gold coins are more expensive than gold bars due to their manufacturing costs and collectible appeal. But both can be used in Gold Individual Retirement Accounts.
Gold IRAs are popular long-term investment vehicles, allowing investors to hold gold as a qualified retirement investment. They are different from regular Retirement plans because they imply the buying and storage of approved bullion products.
Final Words
In this article, we discussed many aspects of the world's most popular precious metal, from its formation through massive stars' nuclear fusion to the planet's core and its upward journey thanks to many natural processes.
Understanding gold's properties and applicability will help you consider and make informed decisions about possible investments.
FAQs
How is gold formed in the Earth?
Gold becomes accessible in the earth's crust due to the earth's activity since heavy metals are usually forced towards the nucleus. However, the element of gold (the periodic table element with the symbol Au, meaning "shining dawn" and a reference to Aurora, the Roman goddess of dawn) is formed by the collision of neutron stars and was deposited at the lower layers of the earth during its formation. Then, it was brought about by many geological processes and also by many meteor strikes in the span of a billion years ago; through hydrothermal processes and forces of erosion, these gold deposits became mineable gold, so it is impossible for the base metals present here to be formed into the gold found.
How long does it take for gold to form naturally?
The most accepted theory is that gold present on our planet was originally formed in the violent collisions of neutron stars. However, due to its dense nature, bringing gold to the surface on Earth takes billions of years. During Earth's initial formation, heavier elements like gold sank towards the core. Over time, it is transported by water, molten lava in volcanic eruptions, and earthquakes that help bring gold deposits closer to the surface. These processes take extensive periods, spanning billions of years, to form accessible gold deposits.
What country did gold originate from?
Gold on Earth, as we know it, was formed in the collision of two neutron stars due to the amount of pressure and intense heat. During the formation of the planet, heavy elements like gold and other metals were deposited at the lower layers of the planet and brought up by many processes. Now, there are a few countries in which gold is more accessible or closer to the planet's surface. China, Australia, Russia, and Canada were the largest producers of gold in the world as of 2023, respectively. But most of the gold on the planet is actually closer to the center and not economically feasible to be mined.
