Gold has fascinated humans for a long time. Gold flakes have been found in Paleolithic caves, with the earliest evidence of interactions dating over 40,000 years ago. Our lust for gold has sparked wars! It divided populations and founded empires. Humans have been actively mining the stuff for over 7,000 years.
With the total world production of gold, the start of civilization reached as high as around 155 thousand tons. It might sound like much of the gold known to have been mined in human history. It bridges the gap between old and new. Ancient cultures used it for things like jewelry and decorating tombs. While in modern times, it can be found treating cancer and coating astronauts, visors, and even computer chips.
What is gold?
Gold is a chemical symbol is AU from the Latin name aurum, meaning “shining dawn.” It is a type of precious metal found in the Earth’s crust. It can be found mixed with other metals or occasionally as a nugget. The biggest nugget found to date weighed over 78 kilograms, and it was nicknamed The Welcome Stranger.
Today, more than 190,000 tons of mined gold globally, 90% of which have been found since the Californian Gold Rush of 1849. It is a rare, valuable, and attractive color. Also, It’s soft enough to be made into many different forms. It doesn’t rust like iron, which can be used for many things. Historically gold has been used for medals, coins, and jewelry.
This ancient gold has been recycled and reused and can be found in phones, medicines, and even spacesuits. It was first mined thousands of years ago, even before the pyramids of Egypt were built. The first civilization to use gold as a form of money was the Kingdom of Lydia in western Turkey in 700 BC. Over the following centuries, gold coins became a common form of money used worldwide.
How is gold formed?
Gold is a heavy metal element with higher masses because they’re made up of more subatomic particles. The lighter elements like oxygen are made by nuclear fusion within stars. It is essentially mashing together pop atoms. But heavier elements like gold can’t be made in this way.
The story of gold is connected with the collision of two neutron stars. Neutron stars are the remains of giant stars bigger than the Sun, whose cores have collapsed at the end of their lives. They’re made up primarily of subatomic particles called neutrons. They’re packed to a density of atomic nuclei. They’re so dense that a single teaspoon would weigh as much as a mountain. The newly born neutron stars can spin as fast as several hundred times every second.
Suppose two of these neutron stars are close enough, their gravitational forces acting upon each other. It could cause a neutron star collision. The collision of these neutron stars results in an explosion that we call Aquila Nova. It is the equivalent of a thousand supernovas. Also, it creates a giant mushroom cloud of glowing material that spreads out away from the site of the collision. The moments after the collision, neutrons, and other subatomic particles start mixing and bunching together. It’s in these moments that gold is formed.
Just one single collision like this can simultaneously produce hundreds of earth masses of gold. So the cloud of material created by the collision continues into the galaxy sending cosmic shrapnel to nearby stars. Star systems at a few tenths of the speed of light. Once the planet’s core formed and the upper layers solidified, large collisions of metallic and rocky objects with our planet provided the outer layers with the precious metal.
Where does the gold come from?
The primary sources of gold can be categorized into two main types: primary deposits and secondary deposits.
Primary Deposits: Gold deposits are formed when gold-rich fluids are transported through cracks and fissures in the Earth’s crust. These fluids are associated with volcanic activity, hydrothermal vents, or magmatic processes. As the fluids cool and interact with different rock formations, gold, and other minerals can precipitate and accumulate in veins or mineralized zones. Primary gold deposits are typically found in active or ancient volcanic areas.
Secondary Deposits: Secondary gold deposits are formed through the erosion and weathering of primary gold deposits. Over time, gold-bearing rocks are exposed to weathering processes such as water, wind, and ice, which break down the rocks and carry away the gold particles. These particles can be transported and deposited in riverbeds, alluvial plains, or sedimentary environments. Secondary gold deposits, or placer deposits, can be found in rivers, streams, and areas where water has historically flowed.
To understand the origin of gold, we first need to visit the periodic table of elements. Gold has an atomic number of 79, meaning it’s heavy. Understanding the origin of gold goes way back in time to the beginning of the universe. Soon after the big bang, only three elements were created hydrogen, helium, and a trace amount of lithium.
About 150 million years later, the first stars formed from these elements. To understand how gold is linked with stars, first learn a few things about the life of a star. Stars spend 90 percent of their life fusing hydrogen into helium in their cores. This crucial phase of their life is known as the main sequence. Sun is a main-sequence star. Technically speaking, it’s the most stable period in the life of a star. It’s a play of two opposite forces. On one side, an inward gravitational force is trying to crush the star. On the other, the outward pressure from nuclear fusion halts the collapse.
Depending on a star’s size, it can take tens of billions of years to convert all the hydrogen into helium. The required temperature for this nuclear reaction is about 15 million kelvin. It shuts down after the core has converted all the hydrogen into helium. That’s because the subsequent fusion reaction converting helium to carbon requires a temperature of 100 million kelvin, which is not there.
Without a nuclear fusion reaction, the balance of the two forces is disturbed, and gravity stars crush the star. This gravitational collapse is a blessing as it increases the star’s temperature.
Helium fuses into carbon once the temperature hits the 100 million kelvin mark. Sun-like mead-sized stars do not have the potential to fuse elements heavier than carbon. But in the case of massive stars, the fusion continues until the iron is formed. Iron is the last element in the fusion chain. That’s because the following nuclear reaction from iron to zinc is endothermic.
In other words, it won’t do any good to the stars. It consumes energy rather than giving it off. Once iron is formed, the core shuts down forever. The star has become so big that gravitational collapse is inevitable by this time. The outer layers of the stars fall onto the core at a rate. That can be one-fifth the speed of light. If the star isn’t too big, these in-falling layers fail to crush the core entirely.
A Quantum mechanical effect called the neutron degeneracy pressure saves the core from a complete collapse. The in-falling layers rebound after colliding with the core, causing shock waves to detonate as a type 2 supernova. The energy produced is so high that it forces electrons and protons to bump together, forming neutrons.
Heavy atoms quickly capture the electrically neutral neutrons, creating even heavier atoms like gold. The formation of these elements takes place within seconds. So when the supernova shock waves shed the debris, heavy elements like gold are dispersed in the interstellar dust, further condensing to form planets and other structures. It is probably one way how gold became a part of our planet.
However, another event can also lead to the creation of gold in the universe. That event is the powerful collision of two neutron stars. Neutron stars are dead stars that have an extremely high density. Within a radius of 10 kilometers, a neutron star can encapsulate a mass 1.5 times that of the sun. In 2017 scientists detected a burst of gravitational waves from an ultra-powerful collision between two neutron stars for the first time. This event is known as a kilonova.
However, the crash was remarkable in another way as well. When astronomers analyzed the wavelength spectrum of this explosion, it pointed to the presence of gold. It was estimated that the collision created about as much gold as the mass of the earth.
Frequently asked questions
Who discovered gold first?
Gold was first discovered in California by James W. Marshall at Sutter’s Mill near Coloma, California. The story goes back to 1848. James was building a sawmill for John Sutter When he saw something shining in the river. They both tested the metal. It was gold. Soon, the word got out; it was no longer a secret. Not many Americans lived in California, but that soon changed. By 1849, thousands upon thousands of people had arrived in search of gold.
The journey to California was dangerous. Some would go by sea from the east coast or on the California Trail. These people would become known as the 49ers. One way to find gold was to pan for it. Miners would sink the pan into the water and shake the dirt away to reveal any gold. Miners needed a lot of equipment, including a mining pan, a shovel, a pick, and food supplies.
Why is gold valuable?
There are a few reasons why gold has become so valued and varied in its uses. For instance, gold is highly malleable and ductile, with a single gram of the stuff being beaten into a sheet measuring one square meter. So it can become semi-transparent.
- Gold is one of the least reactive chemical elements resistant to most acids and resistant to corrosion.
- Gold is also a good conductor of electricity.
On Monday, August 24, 2015, the Dow Jones Industrial Average plummeted nearly 1,100 points. The biggest decline on record in a single trading day. Nearly every time something like this happens, someone comes out of the woodwork saying gold is a better investment. But gold is a pretty rock. How did it become so valuable?
Most of the gold on earth comes from meteorites that smacked down onto the surface two hundred million years after the earth formed. Humans have been fascinated with it for millennia. Gold has been used as currency throughout advanced civilization. The earliest use of gold coins dates back to ancient Egypt, around 500 BCE.
Before coins, there was a system of values based on gold, silver, and copper weights. Romans, Egyptians, and ancient Indians all used gold as a currency. As the modern nation started to adopt paper currency, they used gold to back its value. But we’ve moved away from that. While we don’t use it to back our currency, gold is still highly valued.
- A large amount of gold and silver was found in reservoirs underneath volcanoes in New Zealand. If mined, it could be worth billions for years to come.
Silver makes a great currency: durable and rare enough to be desired. Gold is pretty inert. It’s the least reactive metal, so it won’t rust when exposed to water or oxygen. It won’t ever rust or tarnish. Gold beats out all other metals, even silver, in value because it’s pretty. So all of these attributes make it excellent in various situations and a great store of value.
When did gold become currency?
When the Bank of England was founded in 1694, it became the heart of the gold business in London for the next 300 years. Customers gave their gold coins to look after. In return, they got paper receipts or notes that promised to pay back the coins. Using notes made it easier for people to pay for things. The link between gold and banknotes was known as the gold standard, but the link was broken in 1931. The promise to pay is still there.
How does gold mining work?
Hard rock miners would sink shafts to extract gold from the coarse rock. Drilling was either done by hand well through compressed air drills with the help of a bit of dynamite. Hydraulic drills are the next evolution. These helped open up deeper holes in the Earth’s surface using drill bits which became longer and thinner the further they went down.
Heavy iron stamping machines crushed larger rocks extracted from the mines to release the gold from the surrounding rock. Hydraulic mining uses high-pressure water jets to displace the rock and soil and open the gold beneath.
High in the hills, water was diverted into ditches and heavy iron pipes. As the water channeled down, gravity increased its pressure, reaching 5,000 pounds per square inch. It was pushed through a small nozzle and blasted the mountains apart. The displaced soil cascaded down the valley and into the sluices below, where it would be separated.
While productive, this new mining technique was not without cost. They caused massive flooding in the valleys below by diverting all that water. To solve this problem in California, miners turned to dredge, which worked like a vacuum cleaner, sucking up the material underwater and running it through a sleuth to sift out the gold.
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Nicolas; Avarvari, Narcis; Maigrot, “Gold(I) and Gold(0) Complexes of Phosphinine‐Based Macrocycles”.
Lide, D. R. “Magnetic susceptibility of the elements and inorganic compounds.”
Duckenfield, Mark (2016). The Monetary History of Gold: A Documentary History, 1660–1999. Routledge.
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