Gold

We explain what gold is, its characteristics and physical and chemical properties. Also, its history and its economic importance.

The gold nuggets are yellow and shiny.
Gold is a soft, shiny, golden or yellow mineral, extremely ductile and malleable.

What is gold?

Gold (chemical symbol Au) It is a metallic, heavy and noble chemical element, traditionally considered one of the most coveted precious metals. of the Earth, given its scarcity in nature and its applications in jewelry. It is a soft, shiny, golden or yellow mineral, extremely ductile and malleable, whose name comes from the Latin auruma term that refers to the brightness of the sun at dawn.

Since ancient times, gold has been perceived by humanity as a valuable metal, although it has been used mostly for ornamental purposes. In fact, in heraldry it is a symbol of economic power, as well as greed and vanity. This has made the history of gold different from that of any other metal, since different cultures saw in it a refuge of value to be used for exchange.

The rarity of gold on our planet is due to the fact that the conditions for its formation are extremely specific., as occurs with other heavy elements such as uranium. Gold is created in the collapsing core of supernovae, that is, stars in their final stage of life, within which matter is heated and compressed to such a degree that lighter atoms, such as iron, fuse together. and give rise to heavier elements. There are those who suggest that the gold present on Earth comes from collisions of neutron stars in outer space.

See also: Lead

Characteristics of gold

A jewelry store in Dubai displays its gold pieces.
Gold is a precious metal that is extremely useful in jewelry.

Gold is characterized by the following:

  • It is a chemical element with atomic number 79., that is, each gold atom has 79 protons in the nucleus. In the periodic table it is found along with other coinage metals (such as silver, copper and roentgenium) in group 11.
  • It is a shiny, golden or yellow transition metal., precious and extremely useful in jewelry, despite its relative rarity in the world. It is usually found in its pure state in nature.
  • Does not offer chemical reaction with most known substances, except with cyanide, mercury, chlorine, bleach and aqua regia, compounds in which it can dissolve. It is also immune to air and humidity.
  • Alloys can be made with gold, in which its original tone usually changes. This is how different “types” of gold are obtained, such as blue gold (25% iron), gray gold (15% nickel and 10% copper), red gold (25% copper), pink gold (5% silver and 20% copper), green gold (25% silver) or white gold (16% palladium and 9% silver).
  • In general, It is a good conductor of heat and electricity.
  • Culturally it is associated with wealth and powerand his name is often used as a synonym for worth, money or treasures.
  • 70% of the gold mined goes to jewelry20% to reserves of value and barely 10% to other industrial uses.
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history of gold

The mask in Tutankhamun's tomb is covered in gold.
Gold was used in prehistory and by the great civilizations of Antiquity.

Human beings have known and coveted gold since the origins of civilization. The first traces of gold working date back to the 4th millennium BC. c., in the Chalcolithic period of prehistory, and were found in the necropolis of Varna, in the western region of Bulgaria. Furthermore, the metal It is mentioned in the biblical Old Testament, and in Ancient Egypt it was used in the hieroglyphs of the name of Pharaoh Dyer (3000 BC).

However, From its beginnings, gold was used to manufacture decorative objects. Remains of hats, effigies, rings, bracelets and ritual artifacts made of gold have been found, both in Balkan and European archaeological sites and in those belonging to ancient Mesoamerican cultures. In fact, one of the main impressions of the Spanish conquistadors of the 15th century was the abundance of this precious metal among the objects of the indigenous people, and this gave rise to the myth of a city completely made of gold, called El Dorado.

In medieval times, gold was attributed sanitizing and therapeutic properties., and it was often ingested by the powerful as medicine, crushed into a fine powder, or used to make plates and eating utensils intended to prolong the lives of monarchs. During the Black Death in Europe, gold was experimented with to put an end to the epidemic.

However, The majority use of gold, along with other similar metals, was in the minting of coins from different nations and cultures. But when the value of the metal exceeded the value of the coins themselves, the currencies were backed by the gold kept in the central, royal or national bank, that is, to base the value of a currency on the amount of gold available in the bank. This is known as the “gold standard” and was in effect until the second half of the 20th century.

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The link of gold with wealth is such that Its search and extraction was and continues to be a coveted economic activity. This happened between 1848 and 1960 in some regions of the United States, where there was a massive migration to rural areas, in pursuit of the discovery of gold deposits, which gave rise to what is known as “the gold rush.” .

Chemical and physical properties of gold

The physical-chemical properties of gold can be summarized as follows:

Physical properties of gold:

  • His usual physical state is solid.
  • It is a metal dense (19,300 kg/m3) but soft, ductile and very malleable: with one ounce (31.1 g) of gold you can make a sheet of 28 m2.
  • Have a high melting point (1064 °C) and boiling (2856°C).
  • It is shiny, odorless, tasteless and metallic in texture..
  • It’s a good conductor of heat and electricity.

Chemical properties of gold:

  • Its atomic number is 79its atomic mass is 196.96655 and its most common oxidation states are 1+ and 3+.
  • It is very unreactive and resistant to acids and bases, except in the case of mixtures with bromides, iodides or chlorides.
  • It has only one stable isotope (197Au), the same as its natural origin.
  • It is capable of forming different compoundsbut very few of them are simple.

Where is the gold found?

In an open pit gold mine, machines work to extract the metal.
The largest gold exporters on the planet are China, Australia, Russia, the United States and Peru.

Gold can be found in the earth’s crust, in deposits elevated towards the Earth’s surface due to geological activity. Some studies assume that it could also have a magmatic origin, that is, that it occurs inside the planet. Usually appears in the form of isolated nuggets, or forming minerals such as calaverite, silvanite or nagyagite. There is usually no more than 5% gold for every ton of rock in the Earth’s crust.

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The main gold deposits in the world are found in South Africa, Indonesia, the United States, Peru, Argentina, the Dominican Republic, Russia, China and Australia. However, the largest gold exporters on the planet are China (463.7 tons in 2016), Australia (287.3 tons), Russia (274.4 tons), the United States (225.7 tons) and Peru (166 tons). ).

Gold extraction in both underground and open pit mines involves the use of mercury and arsenic compounds. to separate the precious metal from the rocks, which usually has a very negative impact on both the miners’ bodies and the life around the mine, as they are highly toxic substances.

Economic importance of gold

A gold bar indicates its weight and has its certificate.
Gold is one of the most important metals in the world, whose value is quoted on the stock exchanges.

Gold is one of the most important metals in the world, whose value is quoted on stock exchanges along with other raw materials and international currencies. This is because it has the following economic powers:

  • Is a store of valuegiven that its value is relatively stable compared to other economic goods such as money, whose value fluctuates much more over time.
  • It’s a scarce resourcegiven that not everyone can access it, and also its natural provisions are limited.
  • It’s a investment goodsince it can be bought and sold later to receive a profit when its price is rising.
  • It’s a good intermediatesince it is used as a raw material to produce other consumer goods: jewelry, electrical devices, even some medical drugs.
  • It’s a luxury goodgiven that its demand increases faster than the income of its potential consumers.

Gold is also durable and difficult to counterfeit, making it one of the most coveted and valued resources in the global economy.

Continue with: Lithium

References

  • “Gold mining” on Wikipedia.
  • “Golden Etymology” in the Online Spanish Etymological Dictionary.
  • “How much gold remains to be extracted in the world (and where is the most productive mine in Latin America)” on BBC News Mundo.
  • “Gold in Antiquity” in World History Encyclopedia.
  • “Gold (chemical element)” in The Encyclopaedia Britannica.