Tag der Themenausgabe nächster Tag Uni- und Landesbibliothek in Oldenburg Einarbeiten in das Thema: lesen der Bücher usw. Siedesalzgewinnung Ursprung von Salz Erleichterung Stolz neues gelernt Nach der Facharbeit Great Salt Lake, Utah Meersalzgewinnung Bedeutung des Salzes für. Get this from a library! Weisses Gold: das Salz und die Macht in Europa von bis [Jean-Claude Hocquet; Gerda Kurz].
Golden treasures have been rumored to be found at various locations, following tragedies such as the Jewish temple treasures in the Vatican, following the temple's destruction in 70 AD, a gold stash on the Titanic , the Nazi gold train — following World War II. The Dome of the Rock is covered with an ultra-thin golden glassier. The Sikh Golden temple, the Harmandir Sahib , is a building covered with gold. Similarly the Wat Phra Kaew emerald Buddhist temple wat in Thailand has ornamental gold-leafed statues and roofs.
Some European king and queen's crowns were made of gold, and gold was used for the bridal crown since antiquity. A Greek burial crown made of gold was found in a grave circa BC.
The symbol Au is from the Latin: Outside chemistry, gold is mentioned in a variety of expressions, most often associated with intrinsic worth.
Winners of athletic events and other graded competitions are usually awarded a gold medal. Many awards such as the Nobel Prize are made from gold as well. Aristotle in his ethics used gold symbolism when referring to what is now known as the golden mean. Similarly, gold is associated with perfect or divine principles, such as in the case of the golden ratio and the golden rule. Gold is further associated with the wisdom of aging and fruition.
The fiftieth wedding anniversary is golden. A person's most valued or most successful latter years are sometimes considered "golden years". The height of a civilization is referred to as a golden age. In some forms of Christianity and Judaism , gold has been associated both with holiness and evil. In the Book of Exodus , the Golden Calf is a symbol of idolatry , while in the Book of Genesis , Abraham was said to be rich in gold and silver , and Moses was instructed to cover the Mercy Seat of the Ark of the Covenant with pure gold.
In Byzantine iconography the halos of Christ , Mary and the Christian saints are often golden. According to Christopher Columbus , those who had something of gold were in possession of something of great value on Earth and a substance to even help souls to paradise. Wedding rings have been made of gold. In Orthodox Christian wedding ceremonies, the wedded couple is adorned with a golden crown though some opt for wreaths, instead during the ceremony, an amalgamation of symbolic rites.
The World Gold Council states that as of the end of , "there were , tonnes of stocks in existence above ground". This can be represented by a cube with an edge length of about 21 meters. As of [update] , the world's largest gold producer by far was China with tonnes. The second-largest producer, Australia , mined tonnes in the same year, followed by Russia with tonnes. In China with tonnes overtook South Africa as the world's largest gold producer, the first time since that South Africa has not been the largest.
As of [update] , China was the world's leading gold-mining country, followed in order by Australia, Russia, the United States, Canada, and Peru. South Africa, which had dominated world gold production for most of the 20th century, had declined to sixth place. In South America, the controversial project Pascua Lama aims at exploitation of rich fields in the high mountains of Atacama Desert , at the border between Chile and Argentina.
Today about one-quarter of the world gold output is estimated to originate from artisanal or small scale mining. The city of Johannesburg located in South Africa was founded as a result of the Witwatersrand Gold Rush which resulted in the discovery of some of the largest natural gold deposits in recorded history.
The gold is found only in six areas where archean rivers from the north and north-west formed extensive pebbly Braided river deltas before draining into the "Witwatersrand sea" where the rest of the Witwatersrand sediments were deposited. The Second Boer War of — between the British Empire and the Afrikaner Boers was at least partly over the rights of miners and possession of the gold wealth in South Africa. During the 19th century, gold rushes occurred whenever large gold deposits were discovered.
Gold extraction is most economical in large, easily mined deposits. Ore grades as little as 0. After initial production, gold is often subsequently refined industrially by the Wohlwill process which is based on electrolysis or by the Miller process , that is chlorination in the melt.
The Wohlwill process results in higher purity, but is more complex and is only applied in small-scale installations. According to World Gold Council , China is the world's largest single consumer of gold in and toppled India for the first time with Chinese consumption increasing by 32 percent in a year, while that of India only rose by 13 percent and world consumption rose by 21 percent. Unlike India where gold is mainly used for jewelry, China uses gold for manufacturing and retail. Gold production is associated with contribution to hazardous pollution.
Low-grade gold ore may contain less than one ppm gold metal; such ore is ground and mixed with sodium cyanide to dissolve the gold. Cyanide is a highly poisonous chemical, which can kill living creatures when exposed in minute quantities. Many cyanide spills  from gold mines have occurred in both developed and developing countries which killed aquatic life in long stretches of affected rivers.
Environmentalists consider these events major environmental disasters. When sulfide-bearing minerals in these ore dumps are exposed to air and water, the sulfide transforms into sulfuric acid which in turn dissolves these heavy metals facilitating their passage into surface water and ground water. This process is called acid mine drainage.
These gold ore dumps are long term, highly hazardous wastes second only to nuclear waste dumps. It was once common to use mercury to recover gold from ore, but today the use of mercury is largely limited to small-scale individual miners. Mercury can then enter into the human food chain in the form of methylmercury. Mercury poisoning in humans causes incurable brain function damage and severe retardation.
Gold extraction is also a highly energy intensive industry, extracting ore from deep mines and grinding the large quantity of ore for further chemical extraction requires nearly 25 kWh of electricity per gram of gold produced.
Gold has been widely used throughout the world as money ,  for efficient indirect exchange versus barter , and to store wealth in hoards. For exchange purposes, mints produce standardized gold bullion coins , bars and other units of fixed weight and purity.
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 most 19th century industrial economies. In preparation for World War I the warring nations moved to fractional gold standards, inflating their currencies to finance the war effort.
Post-war, the victorious countries, most notably Britain, gradually restored gold-convertibility, but international flows of gold via bills of exchange remained embargoed; international shipments were made exclusively for bilateral trades or to pay war reparations.
After World War II gold was replaced by a system of nominally convertible currencies related by fixed exchange rates following the Bretton Woods system.
Gold standards and the direct convertibility of currencies to gold have been abandoned by world governments, led in by the United States' refusal to redeem its dollars in gold. Fiat currency now fills most monetary roles. Central banks continue to keep a portion of their liquid reserves as gold in some form, and metals exchanges such as the London Bullion Market Association still clear transactions denominated in gold, including future delivery contracts. Today, gold mining output is declining.
Inventory above ground would satisfy many decades of industrial and even artisan uses at current prices. The gold proportion fineness of alloys is measured by karat k. Pure gold commercially termed fine gold is designated as 24 karat, abbreviated 24k. English gold coins intended for circulation from into the s were typically a standard 22k alloy called crown gold ,  for hardness American gold coins for circulation after contain an alloy of 0.
Although the prices of some platinum group metals can be much higher, gold has long been considered the most desirable of precious metals , and its value has been used as the standard for many currencies.
Gold has been used as a symbol for purity, value, royalty, and particularly roles that combine these properties. Gold as a sign of wealth and prestige was ridiculed by Thomas More in his treatise Utopia. On that imaginary island, gold is so abundant that it is used to make chains for slaves, tableware, and lavatory seats. When ambassadors from other countries arrive, dressed in ostentatious gold jewels and badges, the Utopians mistake them for menial servants, paying homage instead to the most modestly dressed of their party.
Modern bullion coins for investment or collector purposes do not require good mechanical wear properties; they are typically fine gold at 24k, although the American Gold Eagle and the British gold sovereign continue to be minted in 22k 0. The special issue Canadian Gold Maple Leaf coin contains the highest purity gold of any bullion coin , at In , the United States Mint began producing the American Buffalo gold bullion coin with a purity of The Australian Gold Kangaroos were first coined in as the Australian Gold Nugget but changed the reverse design in Like other precious metals, gold is measured by troy weight and by grams.
The proportion of gold in the alloy is measured by karat k , with 24 karat 24k being pure gold, and lower karat numbers proportionally less. The purity of a gold bar or coin can also be expressed as a decimal figure ranging from 0 to 1, known as the millesimal fineness , such as 0.
The price of gold is determined through trading in the gold and derivatives markets, but a procedure known as the Gold Fixing in London , originating in September , provides a daily benchmark price to the industry. The afternoon fixing was introduced in to provide a price when US markets are open. Historically gold coinage was widely used as currency; when paper money was introduced, it typically was a receipt redeemable for gold coin or bullion.
In a monetary system known as the gold standard , a certain weight of gold was given the name of a unit of currency. By , it was becoming hard to maintain this price, and a pool of US and European banks agreed to manipulate the market to prevent further currency devaluation against increased gold demand. Bullion Depository at Fort Knox. In the World Gold Council estimated total global gold supply to be 3, tonnes and demand to be 3, tonnes, giving a surplus of tonnes.
In late , gold markets experienced renewed momentum upwards due to increased demand and a weakening US dollar. Because of the softness of pure 24k gold, it is usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties.
Alloys with lower karat rating , typically 22k, 18k, 14k or 10k, contain higher percentages of copper or other base metals or silver or palladium in the alloy. The Japanese craft of Mokume-gane exploits the color contrasts between laminated colored gold alloys to produce decorative wood-grain effects.
By , the gold jewelry industry was escalating despite a dip in gold prices. Gold solder is used for joining the components of gold jewelry by high-temperature hard soldering or brazing.
If the work is to be of hallmarking quality, the gold solder alloy must match the fineness purity of the work, and alloy formulas are manufactured to color-match yellow and white gold. Gold solder is usually made in at least three melting-point ranges referred to as Easy, Medium and Hard.
By using the hard, high-melting point solder first, followed by solders with progressively lower melting points, goldsmiths can assemble complex items with several separate soldered joints. Gold can also be made into thread and used in embroidery. Though gold is attacked by free chlorine, its good conductivity and general resistance to oxidation and corrosion in other environments including resistance to non-chlorinated acids has led to its widespread industrial use in the electronic era as a thin-layer coating on electrical connectors , thereby ensuring good connection.
For example, gold is used in the connectors of the more expensive electronics cables, such as audio, video and USB cables. The benefit of using gold over other connector metals such as tin in these applications has been debated; gold connectors are often criticized by audio-visual experts as unnecessary for most consumers and seen as simply a marketing ploy. However, the use of gold in other applications in electronic sliding contacts in highly humid or corrosive atmospheres, and in use for contacts with a very high failure cost certain computers , communications equipment, spacecraft , jet aircraft engines remains very common.
Besides sliding electrical contacts, gold is also used in electrical contacts because of its resistance to corrosion , electrical conductivity , ductility and lack of toxicity. Fine gold wires are used to connect semiconductor devices to their packages through a process known as wire bonding. The concentration of free electrons in gold metal is 5. For example, gold electrical wires were used during some of the Manhattan Project 's atomic experiments, but large high-current silver wires were used in the calutron isotope separator magnets in the project.
Metallic and gold compounds have long been used for medicinal purposes. Gold, usually as the metal, is perhaps the most anciently administered medicine apparently by shamanic practitioners  and known to Dioscorides.
Even some modern esotericists and forms of alternative medicine assign metallic gold a healing power. In the 19th century gold had a reputation as a "nervine", a therapy for nervous disorders. Depression , epilepsy , migraine , and glandular problems such as amenorrhea and impotence were treated, and most notably alcoholism Keeley, The apparent paradox of the actual toxicology of the substance suggests the possibility of serious gaps in the understanding of the action of gold in physiology.
Some gold salts do have anti-inflammatory properties and at present two are still used as pharmaceuticals in the treatment of arthritis and other similar conditions in the US sodium aurothiomalate and auranofin. These drugs have been explored as a means to help to reduce the pain and swelling of rheumatoid arthritis , and also historically against tuberculosis and some parasites.
Gold alloys are used in restorative dentistry , especially in tooth restorations, such as crowns and permanent bridges. The gold alloys' slight malleability facilitates the creation of a superior molar mating surface with other teeth and produces results that are generally more satisfactory than those produced by the creation of porcelain crowns.
The use of gold crowns in more prominent teeth such as incisors is favored in some cultures and discouraged in others. Colloidal gold preparations suspensions of gold nanoparticles in water are intensely red- colored , and can be made with tightly controlled particle sizes up to a few tens of nanometers across by reduction of gold chloride with citrate or ascorbate ions. Colloidal gold is used in research applications in medicine, biology and materials science. The technique of immunogold labeling exploits the ability of the gold particles to adsorb protein molecules onto their surfaces.
Colloidal gold particles coated with specific antibodies can be used as probes for the presence and position of antigens on the surfaces of cells. Gold, or alloys of gold and palladium , are applied as conductive coating to biological specimens and other non-conducting materials such as plastics and glass to be viewed in a scanning electron microscope.
The coating, which is usually applied by sputtering with an argon plasma , has a triple role in this application. Gold's very high electrical conductivity drains electrical charge to earth, and its very high density provides stopping power for electrons in the electron beam , helping to limit the depth to which the electron beam penetrates the specimen. This improves definition of the position and topography of the specimen surface and increases the spatial resolution of the image.
Gold also produces a high output of secondary electrons when irradiated by an electron beam, and these low-energy electrons are the most commonly used signal source used in the scanning electron microscope. The isotope gold half-life 2. Pure metallic elemental gold is non-toxic and non-irritating when ingested  and is sometimes used as a food decoration in the form of gold leaf.
Although the gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts gold compounds by any known chemical process which would be encountered in the human body.
Soluble compounds gold salts such as gold chloride are toxic to the liver and kidneys. Common cyanide salts of gold such as potassium gold cyanide, used in gold electroplating , are toxic by virtue of both their cyanide and gold content. There are rare cases of lethal gold poisoning from potassium gold cyanide. Gold metal was voted Allergen of the Year in by the American Contact Dermatitis Society, gold contact allergies affect mostly women.
A sample of the fungus Aspergillus niger was found growing from gold mining solution; and was found to contain cyano metal complexes; such as gold, silver, copper iron and zinc.
The fungus also plays a role in the solubilization of heavy metal sulfides. From Wikipedia, the free encyclopedia. This article is about the element.
For other uses, see Gold disambiguation. For the short story by Fred Hoyle, see Element 79 anthology. This section needs additional citations for verification. February Learn how and when to remove this template message. List of countries by gold production.
Gold mining and Gold prospecting. Mercury cycle and International Cyanide Management Code. Gold as an investment.
Pure and Applied Chemistry. Chemical Rubber Company Publishing. The Monetary History of Gold: A Documentary History, Its scarcity makes it a useful store of value; however, its relative rarity reduced its utility as a currency, especially for transactions in small denominations.
Museums, Objects, and Collections: Rarity is, nevertheless, in itself a source of value, and so is the degree of difficulty which surrounds the winning of the raw material, especially if it is exotic and has to be brought some distance.
Gold is, geologically, a relatively rare material on earth and occurs only in specific places which are remote from most other places. Retrieved 26 December Advanced Media Solutions, Inc. Retrieved 26 March Retrieved 30 December Retrieved 6 June Suiting up for space: Retrieved 18 June The New York Times. Retrieved 25 March As Applied to the Arts and Manufactures , J.
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As of [update] , the world's largest gold producer by far was China with tonnes.
The Wohlwill process results in higher purity, but is more complex and is only applied in small-scale installations. This section needs additional citations for verification.