Gold is an element in the periodic table that has the atomic number 79 and the symbol Au (derived from the Latin word aurum). Because of this, it is considered to be one of the naturally occurring elements with a higher atomic number. In its purest form, the metal possesses a brilliant, slightly orange-yellow hue and is soft, dense, malleable, and ductile. Gold is classified as a group 11 element and a transition metal from a chemistry perspective. It is one of the chemical elements with the lowest rate of reactivity, and it is solid when conditions are normal.

Gold can be found in its “native” or “free elemental” form quite frequently in rocks, veins, and alluvial deposits. This form can take the appearance of nuggets or grains. It can be found in a solid solution series with the native element silver (in the form of electrum), naturally alloyed with other metals such as copper and palladium, as well as mineral inclusions such as those found within pyrite. Rarely, it can be found in minerals as compounds of gold, frequently in combination with tellurium (gold tellurides).

Although gold is resistant to the majority of acids, it can be dissolved in aqua regia, which is a mixture of nitric acid and hydrochloric acid. This process results in the formation of a soluble tetrachloroaurate anion. Nitric acid alone is insoluble in gold, but it can dissolve silver and other base metals. Because of this property, nitric acid has been used for a very long time to refine gold and to confirm the presence of gold in other metallic substances; the term “acid test” comes from this practise. In mining operations and electroplating, alkaline solutions of cyanide are utilised because of gold’s solubility in these solutions. Because the gold merely functions as a solute in this process, we do not consider this to be a chemical reaction. Amalgam alloys can be created when gold is dissolved in mercury.

Gold is a precious metal that has been used throughout recorded history for use in coinage, jewellery, and other forms of artistic expression. Gold is a relatively rare element. A gold standard was frequently used as a basis for previous generations’ monetary policies. During the 1930s, the minting of gold coins as a form of currency was discontinued, and following the shock measures implemented by Nixon in 1971, the world gold standard was replaced with a currency system based on fiat money.

China was the largest producer of gold in the world in the year 2020, followed by Russia and Australia. As of the year 2020, the surface environment hosts a total of approximately 201 296 tonnes of gold. This is equivalent to a cube in which each side is approximately 21.7 metres in length (71 ft). The jewellery industry accounts for approximately fifty percent of the world’s consumption of newly mined gold, while the investment and industrial sectors each take up forty percent.

Gold’s high malleability, ductility, resistance to corrosion and most other chemical reactions, and electrical conductivity have led to its continued use in corrosion-resistant electrical connectors in all different kinds of computerised devices. Gold also has a high melting point, so it can be easily shaped (its chief industrial use). Gold is also utilised in the tooth restoration process, the production of coloured glass, gold leafing, and as a shield against infrared radiation. Certain gold salts are still utilised in the medical field as anti-inflammatory agents.

Characteristics

Gold has a hue that is somewhere between grey and a silvery white, in contrast to the colour of most other metals, which are more of a grey. This colour is determined by the frequency of plasma oscillations among the metal’s valence electrons, which is in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms. These plasma oscillations produce this colour in gold. Similar effects cause the metallic form of caesium to take on a golden hue.

A well-known example of a coloured gold alloy is the distinctive eighteen-karat rose gold that is produced when copper is mixed in with gold. As a result of their ability to produce white gold alloys, alloys containing palladium and nickel are also very important in the commercial jewellery industry.

Both the 14-karat gold-copper alloy and certain bronze alloys can be used to make badges, and both have nearly the same colour. Bronze alloys are also used in some other applications. Green gold is the name given to gold alloys that contain only silver and have karat ratings of fourteen or eighteen. These alloys have an appearance that is greenish-yellow.

The process of alloying gold with iron produces blue gold, and the process of alloying gold with aluminium produces purple gold. Infrequently, the addition of manganese, indium, and various other elements can produce more unusual colours of gold, which can be utilised for a variety of purposes. When the particles of colloidal gold are very small, the material appears red; however, when the particles are much larger, the material appears blue.

Isotopes

Because there is only one stable isotope of gold (197 Au), which is also the only isotope of gold that can be found in nature, gold is considered to be a mononuclidic and monoisotopic element. The atomic masses of the thirty-six radioisotopes that have been artificially produced range from 169 to 205. Among these, 195 Au has the longest half-life: 186.1 days. It is also the most stable. The most unstable is 171 Au, which has a half-life of only 30 microseconds and decays through proton emission.

The majority of radioisotopes of gold that have atomic masses lower than 197 disintegrate through a combination of proton emission, beta decay, and beta+ decay. The only two nuclides that don’t follow this pattern are 195 au, which disintegrates via electron capture, and 196 au, which disintegrates almost exclusively via electron capture (93%) but also follows a minor decay path (7%). The decay mechanism is responsible for the disintegration of all radioisotopes of gold with atomic masses greater than 197.

At least 32 nuclear isomers, ranging in atomic mass from 170 to 200, have also been characterized. These isomers have been found to exist. Only the elements 178 Au, 180 Au, 181 Au, 182 Au, and 188 Au do not have any isomeric forms within this range. The isomer of gold with the longest half-life is 198m2 Au, which has a half-life of 2.27 days. The isomer 177m2 Au of gold is the least stable, with a half-life of only 7 nanoseconds. There are three possible ways for 184m1 Au to decay: + decay, isomeric transition, and alpha decay. There isn’t another isomer or isotope of gold that decays in three different ways.

Synthesis

However, the transmutation of the chemical elements did not become possible until the understanding of nuclear physics in the 20^th century. This has been a topic of human inquiry for a very long time, and the ancient and mediaeval practise of alchemy often focused on the possibility of producing gold from a more common element such as lead. Hantaro Nagaoka, a Japanese physicist, is credited with being the first person to successfully synthesise gold. He did so in 1924 by using neutron bombardment to convert mercury into gold.

In 1941, a group of researchers from the United States carried out the same experiment without being aware of Nagaoka’s earlier research. They were successful in achieving their goal and demonstrated that the isotopes of gold produced as a result of the experiment were all radioactive. At the Lawrence Berkeley Laboratory in 1980, Glenn Seaborg was successful in transforming a few thousand atoms of bismuth into atoms of gold. It is theoretically possible to produce gold in a nuclear reactor, but doing so would be extremely impractical and would incur expenses that are significantly higher than the value of the gold that would be produced.

Chemistry

Gold is the most noble of the noble metals; however, it still forms a wide variety of compounds despite this fact. Gold can have oxidation states ranging from minus one to plus five in its compounds, but the oxidation states Au(I) and Au(III) predominate in its chemical makeup. The aurous ion, also known as Au(I), is the most common oxidation state of the element aurous when it is combined with soft ligands like thioethers, thiolates, and organophosphines. Compounds involving au(I) are typically linear.

An excellent illustration of This is the soluble form of gold that is found in mining, and its chemical formula is Au(CN) 2. Again exhibiting linear coordination at Au, the binary gold halides, such as AuCl, can be formed into zigzag-shaped polymeric chains. The vast majority of gold-based pharmaceuticals are derived from Au(I).

Gold in its most common oxidation state, Au(III), also known as the auric, is depicted by the compound gold(III) chloride, also written as Au2Cl6. The centres of gold atoms in Au(III) complexes, just like the centres of gold atoms in other d8 compounds, are typically square and planar, and the chemical bonds between them have characteristics of both covalent and ionic bonds. One more example of a mixed-valence complex is gold(I,III) chloride, which is known to exist.

Gold does not react with oxygen at any temperature, and it is resistant to the corrosive effects of ozone up to a temperature of one hundred degrees Celsius.

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Gold can be reacted with certain free halogens. At a temperature of dull red, fluorine exerts a strong attack on gold, which results in the formation of gold(III) fluoride, AuF3. At a temperature of 180 degrees Celsius, the reaction between gold powder and chlorine produces gold(III) chloride, also known as AuCl3. At a temperature of 140 degrees Celsius, gold reacts with bromine to produce gold(III) bromide, whereas gold reacts very slowly with iodine to produce gold(I) iodide, AuI.

{\displaystyle {\ce {2 Au + 3 F2 ->[t] 2 AuF3}}}{\displaystyle {\ce {2 Au + 3 F2 ->[t] 2 AuF3}}}

Displaystyle ‘ce ‘2 Au + 3 Cl2 -> ‘t’ 2 AuCl3 displaystyle ‘ce ‘2 Au + 3 Cl2 -> ‘t’ 2 AuCl3 displaystyle ‘ce ‘2 Au + 3 Cl2 -> ‘t’ 2 AuCl3

Displaystyle ce 2 Au + 2 Br2 ->[t] AuBr3 + AuBr displaystyle ce 2 Au + 2 Br2 ->[t] AuBr3 + AuBr displaystyle ce 2 Au + 2 Br2 ->[t] AuBr3 + AuBr

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{\displaystyle {\ce {2 Au + I2 ->[t] 2 AuI}}}

Gold does not interact chemically with sulphur in a direct manner. However, gold(III) sulphide can be produced by filtering hydrogen sulphide through a diluted solution of either gold(III) chloride or chlorauric acid. This process is known as sulfidation.

At room temperature, gold readily dissolves into an amalgam when mercury is present, and at higher temperatures, gold readily forms alloys with a wide variety of other metals. Producing these alloys allows for the modification of the hardness and other metallurgical properties, as well as the control and creation of exotic colours and the ability to control the melting point.

Gold is resistant to the majority of acids. It does not react with hydrofluoric, hydrochloric, hydrobromic, hydriodic, sulfuric, or nitric acid. Aqua regia, which is a mixture of nitric acid and hydrochloric acid in a ratio of 1:3, is able to dissolve it. It will also react with selenic acid. Nitric acid oxidises the metal to produce +3 ions, but only in extremely minute amounts.

As a result of the chemical equilibrium of the reaction, these minute amounts are typically undetectable in the pure acid. However, the ions are eliminated from the equilibrium by hydrochloric acid, which results in the formation of AuCl 4 ions, also known as chloroauric acid. This opens the door for additional oxidation to take place.

Gold is unaffected by the majority of bases in the same way. It does not react with either molten sodium or potassium hydroxide, nor does it react with aqueous sodium or potassium hydroxide. In alkaline conditions and in the presence of oxygen, it does react with sodium or potassium cyanide to form soluble complexes, but this only happens when the cyanide is present.

Gold can exist in a variety of oxidation states, the most common of which are +1 (also known as gold(I) or aurous compounds) and +3 (also known as auric compounds). By adding any other metal as the reducing agent, gold ions in solution can be easily reduced, and the resultant metal can be precipitated. Because the newly added metal oxidises and dissolves, it is possible to recover the gold as a solid precipitate after it has been removed from solution and displaced.

States of oxidation that are uncommon

Gold can also exist in the less frequent oxidation states of -1, +2, and +5.

Aurides, which are compounds that contain the Au+ anion, can exist in the oxidation state known as +1. For instance, caesium auride, also known as CsAu, crystallises in the same pattern as caesium chloride. Other types of aurides, such as rubidium, potassium, and tetramethylammonium, are also known. Due to the fact that gold has the highest electron affinity of any metal, measuring in at 222.8 kJ/mol, the species Au is a stable one, much like the halides.

In the covalent complexes that it forms with the group 4 transition metals, such as titanium tetraauride and the compounds that are analogous to zirconium and hafnium, gold also has an oxidation state of -1. It is anticipated that these chemicals will, in a manner analogous to that of titanium(IV) hydride, produce gold-bridged dimers.

Compounds of gold(II) are typically diamagnetic and contain the bonding structure Au–Au, such as [Au(CH2)2P(C6H5)2]2Cl2. The formation of red crystals of gold(II) sulphate, Au2(SO4)2, results from the evaporation of a solution containing Au(OH)3 that is concentrated in H2SO4.

Despite the fact that it was at first believed to be a compound with mixed valence, recent research has shown that it actually contains cations with the charge of aurium (I) mercury (Hg) 4+ 2 instead. In the compound [AuXe4](Sb2F11), one can find a gold(II) complex known as the tetraxenonogold(II) cation. This complex uses xenon as a ligand.

Gold pentafluoride, along with its derivative anion, AuF 6, and its difluorine complex, gold heptafluoride, is the only example of gold in its highest verified oxidation state, gold(V). Gold heptafluoride is also the only fluoride complex of gold that contains difluorine.

The term “aurophilic bonding” refers to the tendency of gold ions to interact at distances that are too great for a conventional Au–Au bond but are shorter than those required for van der Waals bonding. This interaction can be seen in certain gold compounds. It is hypothesised that the force of this interaction is comparable in magnitude to that of a hydrogen bond.

There are a lot of compounds that can be classified as well-defined clusters. In certain circumstances, the oxidation state of gold is said to be fractional. The octahedral species known as “Au(P(C6H5)3)” 2+ 6 is a good example to illustrate this point.

Origin

Gold is believed to have been produced in supernova nucleosynthesis and from the collision of neutron star. It is also believed that gold was present in the dust that the Solar System formed from.

In the past, it was believed that the r-process, also known as rapid neutron capture, was responsible for the formation of gold in the universe during the process of supernova nucleosynthesis. However, more recently, it has been proposed that the r-process may also be responsible for the production of gold and other elements heavier than iron during the collision of neutron stars.

In both instances, satellite spectrometers were only able to make an indirect discovery of the gold that was produced. However, in August of 2017, electromagnetic observatories observed the spectroscopic signatures of heavy elements such as gold in the GW170817 neutron star merger event. This came after gravitational wave detectors confirmed the event as a neutron star merger.

The astrophysical models that are currently in use suggest that this one neutron star merger event produced between three and thirteen times the mass of Earth in gold. This quantity, in conjunction with estimates of the frequency with which neutron star merger events take place, suggests that such mergers may produce sufficient quantities of gold to account for the majority of the abundance of this element in the universe.

Asteroid origin theories

It is likely that almost all of the gold that was present in the early Earth sank into the core of the planet when the Earth was still in its liquid state during its formation. As a result, the majority of the gold that is found in the crust and the mantle of the earth is thought, according to one model, to have been delivered to the earth later, by asteroid impacts that occurred during the Late Heavy Bombardment approximately 4 billion years ago.

One particular asteroid’s impact has been linked, in at least one instance, to the discovery of gold that is within human reach. It is commonly believed that the asteroid that created the Vredefort impact structure 2.020 billion years ago is responsible for seeding the Witwatersrand basin in South Africa with some of the most lucrative gold deposits on the entire planet.

Having said that, this scenario is being called into question. The gold-bearing rocks of the Witwatersrand were deposited between 700 and 950 million years ago, well in advance of the Vredefort impact. Before the meteor struck, these gold-bearing rocks had also been covered by a thick layer of Ventersdorp lavas and the Transvaal Supergroup of rocks; as a result, the gold did not actually arrive in the asteroid or meteorite.

The Vredefort impact, on the other hand, was successful in deforming the Witwatersrand basin in such a way that the gold-bearing rocks were brought to the present erosion surface in Johannesburg, on the Witwatersrand, just inside the rim of the original crater caused by the meteor strike, which had a diameter of 190 miles (300 kilometres).

The gold rush that began in the Witwatersrand in 1886 was sparked by the discovery of a deposit there. The Witwatersrand rocks have been mined for gold to the extent that 22% of all the gold that is known to exist on Earth today has been extracted from them.

Theories of the mantle return

In spite of the impact described above, it is believed that the majority of the remaining gold on Earth was already a part of the planet when it first formed, when planetesimals were responsible for forming the mantle of the planet and during the early stages of Earth’s formation.

In 2017, a group of scientists from around the world came to the conclusion that gold “came to the surface of the Earth from the deepest regions of our planet,” the mantle. This conclusion was supported by the findings that the group made at Deseado Massif, which is located in the Argentinian Patagonia.

On our planet, gold can be found in the ores that were formed in rock at any time after the Precambrian. It typically occurs as a native metal, most frequently in a metal solid solution with silver (also known as a gold-silver alloy). This is the most common form in which it can be found.

These types of alloys typically have an eight to ten percent silver content. Elemental gold that contains more than 20 percent silver is called electrum, and it is more commonly referred to as white gold. The amount of silver in electrum determines the hue of the metal, which can range from golden-silvery to silvery. When there is a higher concentration of silver, the specific gravity drops.

Native gold is found in the form of very minute to microscopic particles that are embedded in rock. These particles are frequently found in conjunction with quartz or sulphide minerals like “fool’s gold,” which is a pyrite. These types of deposits are known as lode deposits. It is also possible to find the metal in its natural state in the form of free flakes, grains, or larger nuggets that have been eroded from rocks and ended up in alluvial deposits known as placer deposits.

This type of free gold is always richer at the exposed surface of gold-bearing veins. This is due to the oxidation of accompanying minerals, which is then followed by weathering; and by washing of the dust into streams and rivers, where it collects and can be welded together by water action to form nuggets. Both of these processes take place over time.

Gold can sometimes be found associated with tellurium in the form of the minerals calaverite, krennerite, nagyagite, petzite, and sylvanite (see telluride minerals), as well as the extremely rare bismuthide maldonite (Au2Bi) and antimonide aurostibite (AuSb2). Gold can also be found in extremely uncommon alloys with copper, lead, and mercury. These alloys are represented by the minerals auricupride (Cu3Au), novodneprite (AuPb3), and weishanite ((Au,Ag)3Hg2).

Recent studies have shown that microbes can sometimes play a significant role in the formation of gold deposits. These microbes are thought to be responsible for transporting and precipitating gold to form grains and nuggets, which then collect in alluvial deposits.

According to the findings of another recent study, water in faults evaporates during earthquakes, leaving behind deposits of gold. A fault is the path that shaking travels along when an earthquake occurs. In many cases, water acts as a lubricant for faults, allowing it to fill in fractures and jogs. In a region that is approximately 10 kilometres (6.2 miles) below the surface, the water contains high concentrations of carbon dioxide, silica, and gold.

This region is subjected to extremely high temperatures and pressures. When an earthquake happens, the jog in the fault suddenly opens up more. The water that is contained within the void instantly vaporises and transforms into steam. This causes silica, which is the component that makes up the mineral quartz, and gold to be forced out of the fluids and onto the surfaces that are nearby.

Seawater

Gold can be found throughout the world’s oceans. The concentrations of gold that have been measured in the Atlantic and Northeast Pacific are between 10 and 30 parts per quadrillion, which is equivalent to about 10 to 30 grammes per square kilometre. In general, the gold concentrations for samples taken from the south Atlantic and the central Pacific are the same (50 femtomol/L), but the certainty of these values is lower.

The presence of slightly higher concentrations of gold (100–150 femtomol/L), which can be attributed to wind-blown dust and/or rivers, can be found in the deep waters of the Mediterranean. If there were only 10 parts per quadrillion of gold in the oceans, there would be 15,000 tonnes of it. These numbers are three orders of magnitude lower than what was reported in the literature prior to the year 1988, which suggests that there were issues with contamination in the earlier data.

Many individuals have asserted that they are capable of economically extracting gold from ocean water, but these assertions have either been proven to be false or have been made with the intention of misleading others. A con artist named Prescott Jernegan operated a gold-from-seawater scam in the United States during the 1890s, and a con artist from England did the same thing during the early 1900s. In an effort to assist in the payment of Germany’s reparations following World War I, Fritz Haber conducted research on the process of extracting gold from sea water.

An economically viable extraction appeared to be a possibility based on the published values of 2 to 64 ppb for the amount of gold found in seawater. Following the analysis of 4,000 water samples, which produced an average of 0.004 ppb, it became obvious that extraction would not be possible, so he decided to end the project.

History

Gold, which can be found naturally or “native,” appears to have been the first metal ever used by humans, according to historical records. Caves in Spain that date back to the late Paleolithic period (roughly 40,000 years before present) have yielded traces of natural gold in very small amounts.

The oldest gold artefacts in the world come from Bulgaria and date back to the 5^th millennium BC (4,600 BC to 4,200 BC). Examples of these artefacts include those discovered in the Varna Necropolis near Lake Varna and the Black Sea coast. This discovery is believed to be the earliest “well-dated” finding of gold artefacts in the history of the world.

The golden treasures of Hotnitsa and Durankulak, along with artefacts from the Kurgan settlement of Yunatsite near Pazardzhik, the golden treasure Sakar, as well as beads and gold jewellery discovered in the Kurgan settlement of Provadia – Solnitsata (“salt pit”) – are among the prehistoric Bulgarian discoveries that are considered to be of an equally ancient age. However, the gold found in Varna is the one that is generally considered to be the oldest because it is the largest and most varied of all the treasures.

Smelting was developed during the course of the fourth millennium, and gold artefacts probably made their first appearance in Ancient Egypt at the very beginning of the pre-dynastic period, at the end of the fifth millennium BC and at the start of the fourth. Gold artefacts appear in the archaeology of Lower Mesopotamia during the early fourth millennium.

As of the year 1990, the gold artefacts discovered in the Wadi Qana cave cemetery in the West Bank were the earliest to come from the Levant. These artefacts date back to the 4^th millennium BC. Beginning in the second millennium B.C., Central Europe began to see the appearance of gold artefacts, such as the golden hats and the Nebra disc.

The 19^th Dynasty of Ancient Egypt (1320–1200 BC) is when the earliest known map of a gold mine was drawn. On the other hand, the first written reference to gold was recorded during the 12^th Dynasty, which occurred around 1900 BC. Gold is depicted in Egyptian hieroglyphs that date back to as early as 2600 BC. At that time, King Tushratta of the Mitanni asserted that gold was “more plentiful than dirt” in Egypt.

Throughout much of history, Egypt and, more specifically, Nubia were major producers of gold because they possessed the resources necessary to do so. The Turin Papyrus Map, which is considered to be one of the earliest known maps, depicts the layout of a gold mine in Nubia in addition to providing an overview of the geology of the area. Fire-setting is mentioned by both Strabo and Diodorus Siculus as being a part of the earliest known methods of labour, which can be found in both of their accounts. Large mines were also found on the Saudi Arabian side of the Red Sea, which is now known as Saudi Arabia.

The Old Testament makes frequent reference to gold, beginning with Genesis 2:11 (at Havilah), the story of the golden calf, and many parts of the temple, including the golden altar and the Menorah. It is mentioned alongside the gifts brought by the magi in the early chapters of Matthew’s book in the New Testament.

The city of New Jerusalem is said to have streets that are “made of pure gold, clear as crystal” in the Book of Revelation chapter 21 verse 21. It is believed that gold mining in the south-eastern corner of the Black Sea began during the reign of Midas. Around 610 B.C., Lydia began producing coins, which are believed to be the world’s earliest examples of monetary systems.

This gold played an important role in the production of these coins. It’s possible that the legend of the golden fleece, which dates back to the eighth century BCE, refers to the practise of using fleeces to collect gold dust from placer deposits in ancient times. The Ying Yuan was a type of square gold coin that was circulated in the Chu (state) beginning in the sixth or fifth century B.C.

In Roman metallurgy, new techniques for extracting gold on a large scale were developed by introducing hydraulic mining methods, specifically in Hispania beginning in the year 25 BC and in Dacia beginning in the year 106 AD. These techniques were utilised to develop new methods for Roman metallurgy.

They had seven very long aqueducts that allowed them to sluice the majority of a very large alluvial deposit at one of their largest mines, which was located in León and was called Las Medulas. The mines in the Roşia Montană region of Transylvania were also quite large, and up until very recently, they were worked using opencast mining techniques. In addition, they worked on extracting smaller deposits in Britain, such as the placer and hard-rock deposits at Dolaucothi. Pliny the Elder, in his encyclopaedia Naturalis Historia, which was written toward the end of the first century AD, provides a detailed description of the various methods that were utilised by the ancient people.

During Mansa Musa’s (the ruler of the Mali Empire from 1312 to 1337) hajj to Mecca in 1324, he is said to have passed through Cairo in July 1324. It is said that he was accompanied by a camel train that included thousands of people and nearly a hundred camels. It is said that he gave away so much gold that it caused the price of gold in Egypt to drop for over a decade, which led to high inflation. A modern Arab historian made the following observation:

The European exploration of the Americas was fueled in no small part by reports of the gold ornaments displayed in great profusion by Native American peoples, particularly in Mesoamerica, Peru, Ecuador, and Colombia. These regions were particularly attractive to European explorers because of their abundance.

After Moctezuma II was assassinated, the majority of the Aztec nation’s gold was exported to Spain. The Nahuatl word for gold, teocuitlatl, literally translates to “god excrement.” The Aztecs considered gold to be the product of the gods. [93] In spite of this, the indigenous peoples of North America did not place a high value on gold.

Instead, they placed a much higher value on other minerals whose value was directly related to their utility. Some examples of these minerals include obsidian, flint, and slate. [94] The name El Dorado comes from a myth about a city where treasures of all kinds, including gold and precious stones, were discovered in incredible quantities. The idea of El Dorado went through a number of iterations, and in the end, accounts of the earlier myth were also combined with those of a legendary misplaced city.

El Dorado was a mythical tribal chief (zipa) of the Muisca native people in Colombia who, as part of an initiation ritual, covered himself in gold dust and submerged himself in Lake Guatavita. The term “El Dorado” was coined by the Spanish Empire to describe this chief. El Dorado has been various things throughout history, including a man, a city, a kingdom, and finally an empire; as a result, the legends that surround it have evolved over time.

The European exploration and colonisation of West Africa began in the early modern period, and was driven in large part by reports of gold deposits in the region, which was eventually referred to by Europeans as the “Gold Coast.”

Beginning in the late 15^th century and continuing into the early 19^th century, the primary commodity that the Europeans traded in this region was gold, followed by ivory and slaves.

The Ashanti Empire was the dominant force in the gold trade in West Africa. They began their commercial endeavours with the Portuguese and later expanded their business to include trade with merchants from the United Kingdom, France, Spain, and Denmark. The desire of the British government to maintain control of gold deposits in West Africa was a contributing factor in the Anglo-Ashanti wars of the late 19^th century, which resulted in the annexation of the Ashanti Empire by the British.

Gold played a role in western culture as a cause for desire and of corruption, as told in children’s fables such as “Rumpelstiltskin,” in which Rumpelstiltskin turns hay into gold for the peasant’s daughter in exchange for her child when she becomes a princess; and “Jack and the Beanstalk,” in which Jack steals the hen that lays golden eggs from the bean stalk.

The gold medal is considered to be the most prestigious award that can be won at the Olympic Games as well as many other sporting events. Since 1910, 75% of the gold that can be found today has been mined, and over 65% of it has been extracted since 1950.

One of the primary goals of alchemists was to create gold from other materials, such as lead, and this was thought to be accomplished through interaction with a fabled substance known as the philosopher’s stone. The pursuit of producing gold motivated alchemists to investigate the properties of various substances in a methodical manner.

As a result, the groundwork was laid for the development of modern chemistry, which is capable of producing gold (albeit at a high cost) through the process of nuclear transmutation. Their emblem for gold was a circle with a dot in the middle (), which was also the astrological sign for the sun and an ancient Chinese character for the word for the sun.

The thinnest possible layer of golden glassier covers the top of the Dome of the Rock. The Harmandir Sahib, also known as the Golden Temple, is a structure that is entirely covered in gold. In a similar fashion, the ornate gold-leafed statues and roofs of the Wat Phra Kaew emerald Buddhist temple (wat) in Thailand can be found there.

Gold has been used for the bridal crown ever since ancient times, and some of the crowns worn by European kings and queens were made of gold. Rachel, wife of Rabbi Akiva, is said to have been given a “Jerusalem of Gold” in an ancient Talmudic text written around the year 100 AD (diadem). A grave in Greece dating to around 370 BC was discovered to contain a burial crown made of gold.

Etymology

The word “gold” is cognate with a number of other words in a variety of Germanic languages. It is believed that the word “gold” originated from the Proto-Indo-European *helh3- (“to shine, to gleam; to be yellow or green”).

The origin of the symbol Au can be traced back to the Latin word aurum, which means “gold.” The word “glow” is derived from the Proto-Indo-European ancestor of the word “aurium,” which is *h2é-h2us-o. This word is derived from the same root as *h2éuss, the ancestor of the Latin word Aurora, which means “dawn.”

The Proto-Indo-European root is *h2ues-, which means “to dawn.” Because of this etymological connection, it is likely that the phrase “shining dawn” was frequently used in scientific publications to refer to the element aurum.

Culture

Gold is synonymous with achievement in popular culture and appears frequently in the form of awards. Gold, in the form of medals, trophies, and other decorations, is frequently given as a reward for great accomplishments. This can take many forms. Gold medals are typically given out to the victorious athletes and other competitors in various types of competitions. Gold is used in the production of a great deal of awards, including the Nobel Prize. Other award statues and prizes, such as those given out at the Academy Awards, the Golden Globe Awards, the Emmy Awards, the Palme d’Or, and the british Academy Film Awards, are depicted in gold or have a gold plating applied to them.

In his work on ethics, Aristotle used the symbolism of gold to refer to what is now commonly referred to as the golden mean. In a similar vein, gold is connected to ideal or divine principles, such as the case with the golden ratio and the golden rule. Gold is also associated with the experience and maturity that come with advancing years. Golden is the occasion of the fifty-year wedding anniversary. The later years of a person’s life that are considered to be the most valuable or successful are sometimes referred to as their “golden years.” A civilization is said to have reached its “golden age” when it was at its zenith.

Religion

Gold has a complicated history in the religions of Christianity and Judaism, with some sects associating it with both good and evil. In the book of Exodus, the Golden Calf is a representation of idolatry. In the book of Genesis, Abraham is described as being wealthy in gold and silver, and Moses is given the instruction to cover the Mercy Seat of the Ark of the Covenant with pure gold. Both of these passages are found in the Bible. Gold is frequently used for the halo that surrounds Christ, the Virgin Mary, and other saints in Byzantine iconography.

In Islam, men are not permitted to wear silk or gold because both of these materials are considered impure. A hadith was cited by Abu Bakr al-Jazaeri when he stated that “the wearing of silk and gold are forbidden on the males of my nation, and they are lawful to their women.”

This, however, has not been consistently enforced throughout history, such as in the Ottoman Empire. One example of this can be found here. In addition, the use of very subtle gold accents on clothing, such as embroidery, might be acceptable. In the religion and mythology of ancient Greece, Theia was worshipped as the goddess of precious metals and stones, including gold, silver, and a variety of gems.

According to Christopher Columbus, those who possessed gold were in possession of something of great value on Earth and a substance that could even help souls to paradise. Christopher Columbus believed that gold was a pathway to paradise.

Gold is the traditional metal used to craft wedding rings. It is long lasting and unaffected by the passage of time, and it may assist in the ring symbolism of eternal vows before God and the perfection that the marriage signifies. [Case in point:] During the ceremony, which is an amalgamation of symbolic rites, the newlywed couple is typically bestowed with a crown made of gold (although some couples choose to have wreaths placed on their heads instead).

Near the Israeli city of Yavne, in the central region of the country, a group of Israeli archaeologists uncovered a hoard of early Islamic gold coins on August 24, 2020. According to the findings of an examination of the priceless collection of 425 gold coins, the collection dates back to the late 9^th century. The gold coins were from the Abbasid Caliphate and dated back somewhere in the neighbourhood of 1,100 years ago.

Production

South Africa has been the source of a significant portion of the world’s gold supply ever since the 1880s. Approximately 22 percent of the gold that is currently accounted for comes from South Africa. In 1970, production accounted for 79% of the global supply, which was approximately 1,480 tonnes.

In 2007, China (with 276 tonnes) overtook South Africa as the largest gold producer in the world. This marked the first time since 1905 that South Africa had not been the largest gold producer in the world.

China was the most productive gold mining nation in the world in the year 2020, followed by Russia, Australia, the United States of America, Canada, and Ghana in that order.

The contentious project known as Pascua Lama is located in South America and aims to exploit rich fields in the high mountains of the Atacama Desert, which is located on the border between Chile and Argentina. It has been hypothesised that artisanal or small-scale mining accounts for up to one-quarter of the world’s annual gold production.

Because of the discovery of some of the largest natural gold deposits in recorded history, the city of Johannesburg, which is located in South Africa, was founded as a result of the Witwatersrand Gold Rush. Today, Johannesburg is one of the most populous cities in South Africa.

The gold fields are confined to the northern and north-western edges of the Witwatersrand basin, which is a layer of archean rocks between 5 and 7 kilometres (3.1 and 4.3 miles) thick and is located, in most places, deep under the Free State, Gauteng, and the provinces that surround it.

On the Witwatersrand, in and around Johannesburg, as well as in isolated patches to the south-east and south-west of Johannesburg, as well as in an arc around the Vredefort Dome, which lies close to the centre of the Witwatersrand basin, these Witwatersrand rocks are exposed at the surface.

From these surface exposures, the basin drops off significantly, which means that some of the mining must take place at depths of nearly 4,000 metres (13,000 feet). This makes the mines in this region, particularly the Savuka and TauTona mines to the south-west of Johannesburg, the deepest mines on the entire planet.

Only in six locations, where archean rivers from the north and north-west formed extensive pebbly braided river deltas before draining into the “Witwatersrand sea,” which is where the rest of the Witwatersrand sediments were deposited, can gold be found.

At least in part, the rights of miners and ownership of South Africa’s vast gold wealth were at issue during the Second Boer War, which took place between 1899 and 1901 and pitted the British Empire against the Afrikaner Boers.

Gold rushes were common during the 19^th century and occurred whenever large gold deposits were found in new areas. In 1803, gold was discovered for the first time in the United States at a mine called the Reed Gold Mine, which was located close to Georgeville in North Carolina.

Dahlonega, which is located in northern Georgia, is the site of the first significant gold discovery to be made in the United States. Further gold rushes took place in California, Colorado, and the Black Hills, as well as in Otago in New Zealand, a number of locations across Australia, the Witwatersrand in South Africa, and the Klondike in Canada.

Extraction and refining

Large deposits that are simple to mine provide the best economic conditions for gold mining. Economic viability can be achieved with ore grades as low as 0.5 parts per million (ppm). Ore grades in open-pit mines typically range from 1 to 5 ppm, whereas ore grades in underground or hard rock mines typically start at least 3 ppm higher. Because ore grades of thirty parts per million are typically required before gold can be seen with the naked eye, the gold that is extracted from most gold mines is not visible.

In 2007, the average costs of gold mining and extraction were approximately $317 per troy ounce; however, these costs can vary widely depending on the type of mining and the quality of the ore. The total amount of gold mined worldwide was 2,471.1 tonnes.

After the initial production of gold, it is frequently further refined in an industrial setting using either the Wohlwill process, which is predicated on electrolysis, or the Miller process, which involves chlorination of the melt. Both of these processes are described below.

The Wohlwill process yields a higher level of purity, but it is more difficult to implement and can only be used in relatively modest-sized facilities. [128] [129] In addition to parting and inquartation, cupellation and other methods of refining based on the dissolution of gold in aqua regia can be utilised in the process of assaying and purifying smaller quantities of gold.

In the year 2020, the amount of carbon dioxide CO2 produced by mining a kilogramme of gold is expected to be 16 tonnes, while the amount of CO2 equivalent produced by recycling a kilogramme of gold is expected to be 53 kilogrammes. As of the year 2020, recycling will account for approximately thirty percent of the world’s gold supply, which was previously mined.

Companies in a variety of industries, including jewellery manufacturers like Generation Collection and computer manufacturers like Dell, are beginning to implement gold recycling programmes.

Pollution.

The mining of gold is known to contribute to potentially harmful environmental conditions.

Ore with a low concentration of gold, known as low-grade gold ore, is typically ground up and combined with sodium cyanide before the gold can be extracted from it. Cyanide is a highly toxic chemical that, even when exposed to it in trace amounts, is capable of terminating the lives of living organisms.

There have been a significant number of cyanide spills from gold mines in both developed and developing countries, which have resulted in the death of aquatic life in extensive stretches of rivers affected. These events are regarded by environmentalists as major catastrophes for the environment.

One troy ounce of gold can be produced from as much as thirty tonnes of used ore before it is considered waste. Gold ore dumps are a rich source of many heavy elements, including mercury, cadmium, lead, zinc, copper, arsenic, and selenium. When the sulfide-containing minerals in these ore dumps are subjected to air and water, the sulphide undergoes a transformation and becomes sulfuric acid.

This acid then dissolves the heavy metals, making it easier for them to enter surface water and ground water. The term for this kind of process is acid mine drainage. These gold ore dumps are long-term wastes that are extremely hazardous, second only to nuclear waste dumps in terms of their danger.

Mercury was once a widespread practise for extracting gold from its ores; however, in modern times, the use of mercury for this purpose is almost exclusively confined to individual miners working on a small scale.

Even in trace amounts, mercury compounds can make their way into water bodies, which can lead to heavy metal contamination. Methylmercury is a form of mercury that can then make its way into the food chain that humans eat. In humans, ingestion of mercury can result in irreversible damage to brain function as well as severe retardation.

Gold extraction is another industry that uses a significant amount of energy. In order to extract ore from deep mines and grind a large quantity of ore in preparation for additional chemical extraction, nearly 25 kWh of electricity is required for each gramme of gold that is produced.

Monetary used

Gold has a long history of use as a medium of exchange and a means of accumulating wealth. It was first used as money in ancient China and has since spread throughout the world. Mints produce standardised forms of gold bullion, including coins, bars, and other units with a set weight and level of purity, for use in monetary transactions.

Around 600 B.C., the city of Lydia in Asia Minor struck the first coins that are known to have contained gold. The weight of the gold talent coin that was used throughout the history of Greece, including both before and after the time that Homer lived, ranged between 8.42 and 8.75 grammes. This was true for both before and after Homer’s time. [148] Despite an earlier preference for using silver, European economies began minting gold coins during the thirteenth and fourteenth centuries. This was a shift from an earlier preference for using silver.

Bills (that mature into gold coin) and gold certificates (convertible into gold coin at the issuing bank) added to the circulating stock of gold standard money in the majority of industrial economies during the 19^th century. Both of these types of money were issued during the gold standard era. The countries that participated in World War I all adopted fractional gold standards and subsequently inflated their currencies in order to raise more money to fund the conflict. Following the conclusion of the war, the countries that had been victorious, most notably Britain, gradually restored gold-convertibility; however, international flows of gold via bills of exchange remained restricted, and international shipments were only made for the purpose of paying war reparations or conducting bilateral trades.

After the end of World War II, the gold standard was replaced with a system of currencies that were nominally convertible and were related by fixed exchange rates. This system was based on the Bretton Woods agreement. Gold standards and the direct convertibility of currencies to gold have been abandoned by governments around the world.

This trend began in 1971 when the United States refused to redeem its dollars in gold. Other countries followed suit shortly after. The majority of monetary functions are now being fulfilled by fiat currency. Switzerland was the last country in the world to peg its currency to gold until a referendum in 1999 brought an end to the practise.

Metals exchanges such as the London Bullion Market Association still clear transactions denominated in gold, including future delivery contracts. Central banks also continue to keep a portion of their liquid reserves as gold in some form. The amount of gold extracted from mines is currently on the decline. Because of the rapid expansion of economies throughout the 20^th century and the rise in the value of foreign exchange, the world’s gold reserves and their trading market have shrunk to a relatively insignificant portion of all markets.

Additionally, fixed exchange rates of currencies to gold have given way to floating prices for gold and gold future contracts. Even though the gold stock increases by only 1% or 2% annually, very little of the metal is consumed in a way that cannot be recovered. At today’s prices, the inventory above ground would be sufficient to satisfy the needs of the industrial sector and even the artisan sector for many decades.

The karat system is used to quantify the amount of gold contained in various alloys (k). The designation for pure gold, also known as fine gold in the business world, is 24 karat, abbreviated as 24k. Because of its superior hardness, the crown gold alloy was typically used for the production of English gold coins intended for circulation between the years 1526 and the 1930s (American gold coins for circulation after 1837 contain an alloy of 0.900 fine gold, or 21.6 kt).

Although the prices of some metals in the platinum group can be significantly higher at times, gold has historically been regarded as the most desirable of the precious metals, and its value has served as the basis for determining the value of many different currencies. Gold has a long history of serving as a symbol, not only of purity and value but also of royalty and especially of roles that combine these qualities.

Thomas More made fun of gold in his treatise Utopia because he believed it to be a symbol of wealth and prestige. Because there is such a large quantity of gold on that made-up island, it is used for a variety of different things, including tableware and toilet seats. When ambassadors from other countries arrive, dressed in extravagant gold jewels and badges, the Utopians mistake them for lowly servants and pay homage to the member of their party who is the most modestly dressed.

Gold is represented by the ISO 4217 currency code XAU. Even though its effectiveness as a hedge against inflation or other economic disruptions has been questioned; historically, it has not proven itself reliable as a hedging instrument, many owners of gold store it in the form of bullion coins or bars as a hedge against inflation or other economic disruptions.

Even though the American Gold Eagle and the British gold sovereign continue to be minted in 22k (0.92) metal in historical tradition, modern bullion coins for investment or collector purposes do not require good mechanical wear properties. They are typically fine gold at 24k (0.92).

The special issue Canadian Gold Maple Leaf coin contains the highest purity gold of any bullion coin, at 99.999% or 0.99999, whereas the popular issue Canadian Gold Maple Leaf coin has a purity of 99.99%. The coin was designed to honour Canada’s national symbol, the maple leaf, and has been produced in gold since 1979.

The American Buffalo gold bullion coin, which has a purity of 99.99%, was first produced by the United States Mint in the year 2006. Originally issued in 1986 as the Australian Gold Nugget, the reverse design of the coin that would later be known as the Australian Gold Kangaroo was altered in 1989. The bullion coin of the Vienna Philharmonic from Austria and the gold panda from China are both examples of other modern coins.

Gold is measured not only in grammes but also in troy weight, just like other precious metals. The amount of gold that is present in the alloy is expressed as a percentage that is denoted in karats (k), where 24 karats (24k) represents pure gold (100%) and lower karat numbers represent proportionally less gold (18k = 75%). The millesimal fineness of a gold bar or coin can also be expressed as a decimal number ranging from 0 to 1, such as 0.995 for nearly pure gold. This decimal figure can also be expressed as a percentage.

The price of gold is established through trading on the gold and derivatives markets; however, a process that began in September 1919 and is known as the Gold Fixing in London establishes a daily benchmark price for the industry. The afternoon fixing was first implemented in 1968 with the purpose of providing a price when the markets in the United States are open.

When paper money was first introduced, it was typically a receipt that could be redeemed for gold coin or bullion. This remained the case for many years after paper money was first introduced. Throughout the course of history, gold coinage was utilised to a significant degree as a form of currency. A certain quantity of gold was assigned the name of a unit of currency within the context of a monetary system that was commonly referred to as the “gold standard.” Because of this, international trade was facilitated more easily. For a significant portion of time, the United States government was responsible for determining the value of the US Dollar. For a considerable amount of time, the value of one troy ounce was equivalent to $20.67 ($0.665 per gramme).

In 1934, the dollar was devalued to $35.00 per troy ounce, which was equivalent to $0.889 per gramme. This represented a significant increase in value from its previous level. By 1961, it was becoming increasingly difficult to maintain this price, and a group of banks from the United States and Europe came to an agreement to manipulate the market in order to prevent further currency devaluation against increased demand for gold. They did this in order to balance out the demand for gold with the price of gold.

Gold continued to be used to settle international accounts at the old price of $35.00 per troy ounce ($1.13/g), but the price of gold on the private market was allowed to fluctuate. This two-tiered pricing system was abandoned in 1975 when the price of gold was left to find its free-market level. Gold continued to be used to settle international accounts at the old price of $35.00 per troy ounce ($1.13/g). The gold pool went bankrupt on March 17, 1968, as a direct result of the economic climate at the time. A two-tiered pricing scheme was established in its place, and it was mandated that gold would continue to be used to settle international accounts at the previous level of pricing.

In spite of the fact that the amount of gold held in reserves by central banks has, on average, been going down, these financial institutions continue to keep historical gold reserves as a form of value storage. About 3%[160] of the gold that is currently known to exist and has been accounted for is held in either the United States Bullion Depository in Fort Knox or the New York branch of the Federal Reserve Bank of the United States. Both of these facilities are located in the United States.

The Federal Reserve Bank’s location in New York City houses the greatest amount of gold in any single institution in the world. The World Gold Council estimated that the total global supply of gold in 2005 was 3,859 tonnes, while the demand for gold was estimated to be 3,754 tonnes, resulting in a surplus of 105 tonnes. This information can be found in the report that was published in 2005.

After the Nixon shock on August 15, 1971, the price began to significantly increase. Between 1968 and 2000, the price of gold experienced a significant amount of volatility, reaching an all-time high of $850 per troy ounce ($27.33/g) on January 21, 1980, and an all-time low of $252.90 per troy ounce ($8.13/g) on June 21, 1999. The price of gold reached an all-time high of $850 per troy ounce ($27.33/g) on January 21, 1980 (Gold Prices at the London Fixing).

Prices have risen at a rapid pace since 2001; however, the peak that was reached in 1980 was not surpassed until January 3, 2008, when a new maximum price of $865.35 per troy ounce was established. Since then, prices have increased at a rapid pace. The price of gold hit another all-time high on March 17, 2008, when it reached a price of $1023.50 per troy ounce, which is equivalent to $32.91/g.

Late in the year 2009, the gold markets experienced renewed upward momentum due to increased demand as well as a weakening in the value of the US dollar. This was a contributing factor in the rising price of gold.

The price of gold reached a new all-time high of $1,217.23 on December 2, 2009, finishing the day at that level. The ongoing debt crisis in the European Union led to an increase in the number of people purchasing gold as a safe asset.

As a result, gold prices continued their ascent and reached all-time highs in May of 2010. On March 1, 2011, the price of gold hit a new all-time high of $1432.57. This was caused by investor concerns regarding the ongoing unrest in North Africa as well as in the Middle East. Because of this, gold prices reached a new all-time high.