Gold is also used in infrared shielding, colored-glass production, gold leafing , and tooth restoration.
It does not react with hydrofluoric , hydrochloric , hydrobromic , hydriodic , sulfuric , or nitric acid. It does react with selenic acid , and is dissolved by aqua regia , a 1: Gold is similarly unaffected by most bases.
It does not react with aqueous , solid , or molten sodium or potassium hydroxide. It does however, react with sodium or potassium cyanide under alkaline conditions when oxygen is present to form soluble complexes. Gold ions in solution are readily reduced and precipitated as metal by adding any other metal as the reducing agent. The added metal is oxidized and dissolves, allowing the gold to be displaced from solution and be recovered as a solid precipitate.
Caesium auride CsAu , for example, crystallizes in the caesium chloride motif;  rubidium, potassium, and tetramethylammonium aurides are also known.
Some gold compounds exhibit aurophilic bonding , which describes the tendency of gold ions to interact at distances that are too long to be a conventional Au—Au bond but shorter than van der Waals bonding. The interaction is estimated to be comparable in strength to that of a hydrogen bond.
Well-defined cluster compounds are numerous. Medicinal applications of gold and its complexes have a long history dating back thousands of years. Both gold I and gold III compounds have been have been investigated as possible anti-cancer drugs. Stable complexes can be generated using different types of bi-, tri-, and tetradentate ligand systems and their high efficacy has been demonstrated in vitro and in vivo.
Gold is thought to have been produced in supernova nucleosynthesis , and from the collision of neutron stars ,  and to have been present in the dust from which the Solar System formed. Therefore, most of the gold that is in the Earth's crust and mantle is thought to have been delivered to Earth later, by asteroid impacts during the Late Heavy Bombardment , about 4 billion years ago.
Traditionally, gold is thought to have formed by the r-process rapid neutron capture in supernova nucleosynthesis ,  but more recently it has been suggested that gold and other elements heavier than iron may also be produced in quantity by the r-process in the collision of neutron stars. The asteroid that formed Vredefort crater 2.
The discovery of the deposit in launched the Witwatersrand Gold Rush. On Earth, gold is found in ores in rock formed from the Precambrian time onward. Electrum's color runs from golden-silvery to silvery, dependent upon the silver content. The more silver, the lower the specific gravity.
Native gold occurs as very small to microscopic particles embedded in rock, often together with quartz or sulfide minerals such as "Fool's Gold", which is a pyrite. The metal in a native state is also found in the form of free flakes, grains or larger nuggets  that have been eroded from rocks and end up in alluvial deposits called placer deposits.
Such free gold is always richer at the surface of gold-bearing veins [ clarification needed ] owing to the oxidation of accompanying minerals followed by weathering, and washing of the dust into streams and rivers, where it collects and can be welded by water action to form nuggets. Gold sometimes occurs combined with tellurium as the minerals calaverite , krennerite , nagyagite , petzite and sylvanite see telluride minerals , and as the rare bismuthide maldonite Au 2 Bi and antimonide aurostibite AuSb 2.
Gold also occurs in rare alloys with copper , lead , and mercury: Recent research suggests that microbes can sometimes play an important role in forming gold deposits, transporting and precipitating gold to form grains and nuggets that collect in alluvial deposits.
Another recent study has claimed water in faults vaporizes during an earthquake, depositing gold. When an earthquake strikes, it moves along a fault. Water often lubricates faults, filling in fractures and jogs. About 6 miles 10 kilometers below the surface, under incredible temperatures and pressures, the water carries high concentrations of carbon dioxide, silica, and gold. During an earthquake, the fault jog suddenly opens wider. The water inside the void instantly vaporizes, flashing to steam and forcing silica, which forms the mineral quartz, and gold out of the fluids and onto nearby surfaces.
The world's oceans contain gold. At 10 parts per quadrillion the Earth's oceans would hold 15, tonnes of gold. A number of people have claimed to be able to economically recover gold from sea water , but they were either mistaken or acted in an intentional deception. Prescott Jernegan ran a gold-from-seawater swindle in the United States in the s, as did an English fraudster in the early s.
After analysis of 4, water samples yielding an average of 0. As of , gold artifacts found at the Nahal Qana cave cemetery of the 4th millennium BC were the earliest from the Levant. The oldest known map of a gold mine was drawn in the 19th Dynasty of Ancient Egypt — BC , whereas the first written reference to gold was recorded in the 12th Dynasty around BC.
One of the earliest known maps, known as the Turin Papyrus Map , shows the plan of a gold mine in Nubia together with indications of the local geology. The primitive working methods are described by both Strabo and Diodorus Siculus , and included fire-setting. Large mines were also present across the Red Sea in what is now Saudi Arabia.
Gold is mentioned in the Amarna letters numbered 19  and 26  from around the 14th century BC. Gold is mentioned frequently in the Old Testament , starting with Genesis 2: In the New Testament , it is included with the gifts of the magi in the first chapters of Matthew. The Book of Revelation Exploitation of gold in the south-east corner of the Black Sea is said to date from the time of Midas , and this gold was important in the establishment of what is probably the world's earliest coinage in Lydia around BC.
From the 6th or 5th century BC, the Chu state circulated the Ying Yuan , one kind of square gold coin. In Roman metallurgy , new methods for extracting gold on a large scale were developed by introducing hydraulic mining methods, especially in Hispania from 25 BC onwards and in Dacia from AD onwards. They also exploited smaller deposits in Britain , such as placer and hard-rock deposits at Dolaucothi.
The various methods they used are well described by Pliny the Elder in his encyclopedia Naturalis Historia written towards the end of the first century AD. During Mansa Musa 's ruler of the Mali Empire from to hajj to Mecca in , he passed through Cairo in July , and was reportedly accompanied by a camel train that included thousands of people and nearly a hundred camels where he gave away so much gold that it depressed the price in Egypt for over a decade, causing high inflation.
Gold was at a high price in Egypt until they came in that year. The mithqal did not go below 25 dirhams and was generally above, but from that time its value fell and it cheapened in price and has remained cheap till now. The mithqal does not exceed 22 dirhams or less. This has been the state of affairs for about twelve years until this day by reason of the large amount of gold which they brought into Egypt and spent there [ 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, especially in Mesoamerica , Peru , Ecuador and Colombia.
The Aztecs regarded gold as the product of the gods, calling it literally "god excrement" teocuitlatl in Nahuatl , and after Moctezuma II was killed, most of this gold was shipped to Spain. Gold played a role in western culture, as a cause for desire and of corruption, as told in children's fables such as Rumpelstiltskin —where Rumpelstiltskin turns hay into gold for the peasant's daughter in return for her child when she becomes a princess—and the stealing of the hen that lays golden eggs in Jack and the Beanstalk.
The top prize at the Olympic Games and many other sports competitions is the gold medal. Although they never succeeded in this attempt, the alchemists did promote an interest in systematically finding out what can be done with substances, and this laid the foundation for today's chemistry.
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.
These extra 2 digits stands for the manufacturer of the paint and the type of finishing that has been used. The fourth digit of the code indicates the manufacturer and the fifth digit represents the sort of paint. The paint usually was made bij Glausarit and Herberts. The manufacturer code 6 was only used for experimental purposes and was made by Lewis and some other manufacturers mostly local suppliers.
The producer of the paint can be found at the fourth digit of the paint code. The fifth digit represents the type of paint and the kind of finish that has been used: In the chart below you can find all the colors Volvo has used from till now color codes from 00 until 18 were used for the first cars, army vehicles, busses and trucks. Samples are also included, however the color might slightly vary. I used the original Volvo-brochures and color samples to complete this list.
Hello, I have just been checking out the colour codes on this page for my Volvo GL New project acquired last April to go with my S. May I suggest that you check out the colour chart since the car is definitely wearing factory paint over most of its surfaces? The colorsample in the chart above is taken from the original brochure of the Volvo , so it should be the right color.
I will renew the color in a couple of days in the darker version. Thanks for the notice! OC Auto Exchange Call: My Account My Account.
Year 1 7 26 50 89 30 22 10 13 6 6 5 5 4 4 6 3. Peace of Mind Free CarFax on every car. Rates as low as 1. Customer Reviews David E. Online Appraisal Schedule onsite visit to cash in your vehicle. Locate Us S. Fullerton, CA Sales:
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