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Gold: the story on HearLore | HearLore
Gold
Gold is the only metal that exists in nature as a solid, pure element, yet it is so rare that if you gathered every ounce ever mined in human history, it would form a single cube measuring just 21 meters on each side. This dense, yellow metal, with the chemical symbol Au and atomic number 79, possesses a unique duality: it is the most malleable of all metals, capable of being beaten into sheets so thin they become semi-transparent, yet it is also the most chemically inert, resisting corrosion and reaction with almost every substance known to science. While most metals oxidize and crumble into dust when exposed to air, gold remains unchanged for millennia, a property that has made it the eternal standard for value and the subject of human obsession for over 6,000 years. The very existence of gold on Earth's surface is a cosmic accident, as the planet's molten core swallowed almost all of the original gold during its formation, leaving only the gold delivered by asteroid impacts billions of years ago to be found by human hands.
Cosmic Origins And Earthly Myths
The gold found in the earth's crust did not form here; it was forged in the violent collisions of neutron stars and the explosive flares of magnetars, events that occurred billions of years before the Earth itself existed. Scientists have confirmed that the gold present in the universe is the result of the r-process, a rapid neutron capture that happens during supernova nucleosynthesis and, more significantly, during the merger of two neutron stars. In August 2017, astronomers directly observed the spectroscopic signatures of heavy elements, including gold, during the GW170817 neutron star merger event, proving that a single such collision could generate between 3 and 13 Earth masses of gold. Despite this cosmic abundance, the gold accessible to humans is a remnant of the Late Heavy Bombardment, approximately 4 billion years ago, when asteroids struck the molten Earth and deposited their precious cargo into the crust. One specific impact, the Vredefort crater event 2.020 billion years ago, is credited with bringing the gold-bearing rocks of the Witwatersrand basin to the surface in South Africa, creating the richest gold deposits on Earth. This geological anomaly, formed by ancient rivers depositing gold into a sea before being buried by lava and later exposed by erosion, launched the Witwatersrand Gold Rush in 1886 and accounts for 22% of all the gold ascertained to exist today.
The Alchemists And The Kings
For centuries, the pursuit of gold drove the history of human civilization, from the earliest recorded metal artifacts found in the Varna Necropolis in Bulgaria dating back to the 5th millennium BC to the golden treasures of the Egyptian pharaohs. The ancient Egyptians viewed gold as the flesh of the gods, and the first known gold coins were struck in Lydia, Asia Minor, around 600 BC, establishing a monetary system that would eventually span the globe. The legend of the Golden Fleece, dating from the 8th century BC, may refer to the practical use of fleeces to trap gold dust from placer deposits, a technique that allowed ancient civilizations to harvest gold from rivers. In the Roman Empire, hydraulic mining methods were developed to extract gold on a massive scale, with the mines at Las Medulas in Spain utilizing seven long aqueducts to sluice away entire hillsides. The history of gold is also a history of greed and power, exemplified by Mansa Musa, the ruler of the Mali Empire, whose pilgrimage to Mecca in 1324 included a camel train of nearly a hundred camels and thousands of people. His distribution of gold in Cairo depressed the price of the metal for over a decade, causing high inflation that took years to recover. The European exploration of the Americas was fueled by reports of gold ornaments, with the Aztecs calling gold teocuitlatl, or god excrement, while the Spanish shipped vast quantities of it back to Europe, driving the economic expansion of the continent.
What is the chemical symbol and atomic number of gold?
Gold has the chemical symbol Au and the atomic number 79. This dense, yellow metal is the only element that exists in nature as a solid, pure element.
How was gold formed and delivered to Earth?
Gold was forged in the violent collisions of neutron stars and the explosive flares of magnetars billions of years before Earth existed. It was delivered to the planet's crust by asteroid impacts during the Late Heavy Bombardment approximately 4 billion years ago.
When did the Witwatersrand Gold Rush begin and what percentage of gold does it account for?
The Witwatersrand Gold Rush began in 1886 following the geological anomaly created by the Vredefort crater event 2.020 billion years ago. This region accounts for 22% of all the gold ascertained to exist today.
What was the highest and lowest recorded price of gold per troy ounce?
The price of gold reached a high of $850 per troy ounce on the 21st of January 1980 and a low of $252.90 per troy ounce on the 21st of June 1999. It later hit a new all-time high of $1,913.50 on the 23rd of August 2011.
How much gold exists above ground and which country produces the most?
There are around 201,296 tonnes of gold existing above ground today. China is the world's largest gold producer, followed by Russia and Australia.
What are the environmental costs of gold mining and how much energy does it require?
Gold production is associated with hazardous pollution from sodium cyanide and mercury, causing environmental disasters and heavy metal contamination. The industry requires nearly 25 kilowatt-hours of electricity per gram of gold produced and generates 16 tonnes of carbon dioxide for every kilogram mined.
Gold's unique properties extend far beyond its visual appeal, as it is the most malleable metal known, capable of being drawn into a wire of single-atom width and stretched considerably before it breaks. This malleability allows a single gram of gold to be beaten into a sheet of 1 square meter, and an avoirdupois ounce into 300 square meters, creating gold leaf that is so thin it becomes semi-transparent. The yellow color of gold is a well-known example of relativistic quantum chemistry, where the 5d-6s band gap is greatly reduced when relativity is included in theoretical calculations, causing the metal to absorb blue light and reflect yellow and red. Gold is also a good conductor of heat and electricity, making it the preferred material for corrosion-free electrical connectors in all types of computerized devices. Despite its resistance to most acids, gold dissolves in aqua regia, a mixture of nitric acid and hydrochloric acid, forming a soluble tetrachloroaurate anion. This property, along with its ability to dissolve in alkaline solutions of cyanide, has been used in mining and electroplating for over a century. The chemistry of gold is diverse, with oxidation states ranging from -1 to +5, and it forms compounds with tellurium, mercury, and various other metals, creating alloys that can be colored green, blue, or purple depending on the elements added.
The Modern Economy And The Nixon Shock
The global economy has been inextricably linked to gold for millennia, with the first known gold coins struck in Lydia around 600 BC and the gold standard implemented as a monetary policy in many nations. In the United States, the government set the value of the dollar so that one troy ounce was equal to $20.67, but in 1934 the dollar was devalued to $35.00 per troy ounce. The system of fixed exchange rates and gold convertibility was abandoned by world governments, led in 1971 by the United States' refusal to redeem its dollars in gold, an event known as the Nixon shock. This decision marked the end of the Bretton Woods system and the beginning of the fiat currency era, where the value of money is not backed by a physical commodity. Despite this, gold remains a critical component of global finance, with the largest gold depository in the world located at the U.S. Federal Reserve Bank in New York, holding about 3% of the gold known to exist. The price of gold has fluctuated wildly over the centuries, ranging from a high of $850 per troy ounce on the 21st of January 1980 to a low of $252.90 per troy ounce on the 21st of June 1999, before hitting a new all-time high of $1,913.50 on the 23rd of August 2011. Today, the world's largest gold producer is China, followed by Russia and Australia, with a total of around 201,296 tonnes of gold existing above ground.
The Dark Side Of The Shine
The pursuit of gold has come at a significant environmental and human cost, with gold production associated with hazardous pollution and the destruction of ecosystems. Low-grade gold ore may contain less than one part per million of gold metal, requiring the use of sodium cyanide to dissolve the gold, a highly poisonous chemical that can kill living creatures when exposed in minute quantities. Many cyanide spills from gold mines have occurred in both developed and developing countries, killing aquatic life in long stretches of affected rivers and causing environmental disasters comparable to the Chernobyl nuclear disaster. The process of acid mine drainage, where sulfide-bearing minerals in gold ore dumps are exposed to air and water, transforms into sulfuric acid which dissolves heavy metals like cadmium, lead, zinc, copper, arsenic, selenium, and mercury, facilitating their passage into surface water and ground water. The use of mercury to recover gold from ore, though largely limited to small-scale individual miners today, has caused heavy metal contamination in water bodies, leading to mercury poisoning in humans and severe brain damage. Gold extraction is also a highly energy-intensive industry, requiring nearly 25 kilowatt-hours of electricity per gram of gold produced, and the carbon dioxide produced in mining a kilogram of gold is 16 tonnes, while recycling a kilogram of gold produces 53 kilograms of carbon dioxide equivalent.
The Future Of The Precious Metal
Despite the environmental costs and the shift to fiat currencies, gold remains a vital component of modern technology and medicine, with 10% of the world's consumption of new gold produced going to industry. Gold is used in the fabrication of corrosion-free electrical connectors in computers and other electrical devices, with a typical cell phone containing 50 milligrams of gold, worth about three dollars. The use of gold in electronics is critical for ensuring good connection in highly humid or corrosive atmospheres, and in use for contacts with a very high failure cost, such as in spacecraft and jet aircraft engines. In medicine, gold compounds are used to treat rheumatoid arthritis and other similar conditions, and the isotope gold-198 is used in nuclear medicine for cancer treatments. Gold is also used in restorative dentistry, where its slight malleability facilitates the creation of a superior molar mating surface with other teeth. The future of gold may lie in its ability to be manufactured so thin that it appears semi-transparent, used in aircraft cockpit windows for de-icing or anti-icing by passing electricity through it. The gold industry continues to evolve, with the world's largest gold mine, Grasberg, located in Papua, Indonesia, and the development of new mining techniques to extract gold from deep underground.