Gold

Aunative goldgold dustlode goldgold jewelryAuricgildedgiltgold buggold leaf
Gold is a chemical element with the symbol Au (from aurum) and atomic number 79, making it one of the higher atomic number elements that occur naturally.wikipedia
6,835 Related Articles

Gold nugget

nuggetnuggetsgold nuggets
Gold often occurs in free elemental (native) form, as nuggets or grains, in rocks, in veins, and in alluvial deposits.
A gold nugget is a naturally occurring piece of native gold.

Alloy

alloysmetal alloyalloying
It occurs in a solid solution series with the native element silver (as electrum) and also naturally alloyed with copper and palladium.
For example, combining the metallic elements gold and copper produces red gold, gold and silver becomes white gold, and silver combined with copper produces sterling silver.

Silver

Agsilver orenative silver
It occurs in a solid solution series with the native element silver (as electrum) and also naturally alloyed with copper and palladium.
The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite.

Gold standard

goldgold exchange standardbacked by gold
In the past, a gold standard was often implemented as a monetary policy, but gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard was abandoned for a fiat currency system after 1971.
A gold standard is a monetary system in which the standard economic unit of account is based on a fixed quantity of gold.

Group 11 element

group 1111coinage metals
Chemically, gold is a transition metal and a group 11 element.
Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), and gold (Au).

Base metal

base metalsbase base metals
Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to refine gold and to confirm the presence of gold in metallic objects, giving rise to the term acid test.
A base metal is a common and inexpensive metal, as opposed to a precious metal such as gold or silver.

Gold leaf

gold foilgold-leafgold
Gold is also used in infrared shielding, colored-glass production, gold leafing, and tooth restoration.
Gold leaf is gold that has been hammered into thin sheets by goldbeating and is often used for gilding.

Chemical element

elementelementschemical elements
Gold is a chemical element with the symbol Au (from aurum) and atomic number 79, making it one of the higher atomic number elements that occur naturally.
Among the more common of such native elements are copper, silver, gold, carbon (as coal, graphite, or diamonds), and sulfur.

Copper

CuCu 2+ cupric
It occurs in a solid solution series with the native element silver (as electrum) and also naturally alloyed with copper and palladium.
Copper, silver, and gold are in group 11 of the periodic table; these three metals have one s-orbital electron on top of a filled d-electron shell and are characterized by high ductility, and electrical and thermal conductivity.

Ductility

ductilemalleablemalleability
In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal.
Ductility and malleability are not always coextensive – for instance, while gold has high ductility and malleability, lead has low ductility but high malleability; one ounce of gold can be drawn into more than 80 Km of thin gold wire.

Aqua regia

aqua regisNitrohydrochloric acidnitromuriatic acid
Gold is resistant to most acids, though it does dissolve in aqua regia, a mixture of nitric acid and hydrochloric acid, which forms a soluble tetrachloroaurate anion.
Aqua regia is a yellow-orange (sometimes red) fuming liquid, so named by alchemists because it can dissolve the noble metals gold and platinum, though not all metals.

Colored gold

white goldred goldrose gold
Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper.
Pure gold is slightly reddish yellow in color, but colored gold in various other colors can be produced.

List of countries by gold production

world's largest2310Gold
, the world's largest gold producer by far was China with 440 tonnes per year.
Until 2006 South Africa was the world's largest gold producer.

Gold mining in China

Chinagoldgold deposit
, the world's largest gold producer by far was China with 440 tonnes per year.
Gold mining in the People's Republic of China has made that country the world's largest gold producer by far with 463.7 tonnes in 2016.

Precious metal

precious metalsbullionprecious
A relatively rare element, gold is a precious metal that has been used for coinage, jewelry, and other arts throughout recorded history.
Gold, silver, platinum, and palladium each have an ISO 4217 currency code.

Chemical reaction

reactionchemical reactionsreactions
Gold dissolves in mercury, forming amalgam alloys, but this is not a chemical reaction.
They attempted, in particular, to convert lead into gold, for which purpose they used reactions of lead and lead-copper alloys with sulfur.

Tungsten

WwolframTungsten (W)
Gold has a density of 19.3 g/cm 3, almost identical to that of tungsten at 19.25 g/cm 3 ; as such, tungsten has been used in counterfeiting of gold bars, such as by plating a tungsten bar with gold, or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods.
Its density is 19.25 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead.

Gold salts

gold saltaurotherapychrysotherapy
Certain gold salts are still used as anti-inflammatories in medicine.
Gold salts are ionic chemical compounds of gold.

Nixon shock

Dollar hegemonyclosed the gold windowsuspension in 1971
In the past, a gold standard was often implemented as a monetary policy, but gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard was abandoned for a fiat currency system after 1971.
The Nixon shock was a series of economic measures undertaken by United States President Richard Nixon in 1971, in response to increasing inflation, the most significant of which were wage and price freezes, surcharges on imports, and the unilateral cancellation of the direct international convertibility of the United States dollar to gold.

Electrum

green goldargentian goldalloy of the same name
It occurs in a solid solution series with the native element silver (as electrum) and also naturally alloyed with copper and palladium.
Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals.

Gold bar

gold bullionbarsgold bars
Gold has a density of 19.3 g/cm 3, almost identical to that of tungsten at 19.25 g/cm 3 ; as such, tungsten has been used in counterfeiting of gold bars, such as by plating a tungsten bar with gold, or taking an existing gold bar, drilling holes, and replacing the removed gold with tungsten rods.
A gold bar, also called gold bullion or a gold ingot, is a quantity of refined metallic gold of any shape that is made by a bar producer meeting standard conditions of manufacture, labeling, and record keeping.

Mercury (element)

mercuryquicksilverHg
Gold dissolves in mercury, forming amalgam alloys, but this is not a chemical reaction.
Mercury dissolves many metals such as gold and silver to form amalgams.

Acid test (gold)

acid testacid test for goldacid tests
Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to refine gold and to confirm the presence of gold in metallic objects, giving rise to the term acid test.
An acid test is any qualitative chemical or metallurgical assay which uses acid; most commonly, and historically, the use of a strong acid to distinguish gold from base metals.

Relativistic quantum chemistry

relativistic effectsrelativisticrelativistic effect
This color is determined by the frequency of plasma oscillations among the metal's valence electrons, in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms.
A prominent example of such an explanation is the color of gold: due to relativistic effects, it is not silvery like most other metals.

Alchemy

alchemistalchemicalalchemists
The production of gold from a more common element, such as lead, has long been a subject of human inquiry, and the ancient and medieval discipline of alchemy often focused on it; however, the transmutation of the chemical elements did not become possible until the understanding of nuclear physics in the 20th century.
Common aims were chrysopoeia, the transmutation of "base metals" (e.g., lead) into "noble metals" (particularly gold); the creation of an elixir of immortality; the creation of panaceas able to cure any disease; and the development of an alkahest, a universal solvent.