181-414: Gold mining is the extraction of gold by mining . Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning . The expansion of gold mining to ores that are not on the surface has led to more complex extraction processes such as pit mining and gold cyanidation . In the 20th and 21st centuries, most volume of mining was done by large corporations. However,
362-399: A fault . Water often lubricates faults, filling in fractures and jogs. About 10 kilometres (6.2 mi) below the surface, under very high 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
543-434: A solid solution series with the native element silver (as in electrum ), naturally alloyed with other metals like copper and palladium , and mineral inclusions such as within pyrite . Less commonly, it occurs in minerals as gold compounds, often with tellurium ( gold tellurides ). Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid ), forming
724-709: A combination of factors including the depletion of easily accessible gold deposits, harsh weather conditions, and the political instability at the time. The Welsh gold rush occurred in Wales , more so in the Dolgellau area of Gwynedd , during the 19th century. Gold deposits were discovered in Welsh mountains, with reports of gold being found in rivers Mawddach and Tryweryn . By the mid-19th century, commercial mining operations had begun. Wales' gold gained popularity for its quality and rarity, leading to its use in royal jewelry for
905-719: A critical source of income and livelihood, providing employment opportunities and economic support in regions with limited alternative options. Artisanal mining operations vary in scale, from individuals panning for gold in rivers and streams, to small groups working collectibely in informal mining camps, often referred to as ' galamsey ' in West Africa . Gold mining can create employment opportunities in mining operations and related sectors. Howevers, these jobs may be temporary. The sector's reliance on fluctuating global gold prices can lead to economic stability for communities dependent on mining. The discovery of significant gold deposits in
1086-483: A dilute solution of gold(III) chloride or chlorauric acid . Unlike sulfur, phosphorus reacts directly with gold at elevated temperatures to produce gold phosphide (Au 2 P 3 ). Gold readily dissolves in mercury at room temperature to form an amalgam , and forms alloys with many other metals at higher temperatures. These alloys can be produced to modify the hardness and other metallurgical properties, to control melting point or to create exotic colors. Gold
1267-579: A gold-from-seawater swindle in the United States in the 1890s, as did an English fraudster in the early 1900s. Fritz Haber did research on the extraction of gold from sea water in an effort to help pay Germany 's reparations following World War I . Based on the published values of 2 to 64 ppb of gold in seawater, a commercially successful extraction seemed possible. After analysis of 4,000 water samples yielding an average of 0.004 ppb, it became clear that extraction would not be possible, and he ended
1448-830: A golden hue to metallic caesium . Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper. Alloys containing palladium or nickel are also important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain bronze alloys, and both may be used to produce police and other badges . Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and are referred to as green gold . Blue gold can be made by alloying with iron , and purple gold can be made by alloying with aluminium . Less commonly, addition of manganese , indium , and other elements can produce more unusual colors of gold for various applications. Colloidal gold , used by electron-microscopists,
1629-435: A gravel screening plant and sluice box floating in a temporary pond. The pond is excavated in the gravel bar and filled from the natural water table. "Pay" gravel is excavated from the front face of the pond and processed through the floating plant, with the gold trapped in the onboard sluice box and tailings stacked behind the plant, steadily filling in the back of the pond as the operation moves forward. This type of gold mining
1810-567: A large alluvial deposit. The mines at Roşia Montană in Transylvania were also very large, and until very recently, still mined by opencast methods. 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
1991-699: A leader of the opposition to Antonescu, entered into secret negotiations with British diplomats who made it clear that Romania had to seek reconciliation with the Soviet Union. To facilitate the coordination of their activities against Antonescu's regime, the National Liberal and National Peasants' parties established the National Democratic Bloc, which also included the Social Democratic and Communist parties. After
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#17327930934792172-486: A lower grade. Tailings can contain lead, mercury, cadmium, and arsenic. These toxins can pose health risks for local communities. Arsenic is typically found in gold-containing ores, and gold processing may contaminate groundwater or the atmosphere. This pollution may persist for decades. Furthermore, mining operations use large quantities of water for processing ore and can result in the contamination of water sources with heavy metals, such as mercury and cyanide , used in
2353-638: A mainly continental climate , and an area of 238,397 km (92,046 sq mi) with a population of 19 million people (2023). Romania is the twelfth-largest country in Europe and the sixth-most populous member state of the European Union . Europe's second-longest river, the Danube , empties into the Danube Delta in the southeast of the country. The Carpathian Mountains cross Romania from
2534-479: A member of the Warsaw Pact , transitioning to democracy and a market economy after the 1989 Revolution . Romania is a developing country with a high-income economy , recognized as a middle power in international affairs . It hosts several UNESCO World Heritage Sites and is a growing tourist attraction, receiving 13 million foreign visitors in 2023 . Its economy ranks among the fastest growing in
2715-501: A new state under Ottoman suzerainty, the Principality of Transylvania . Reformation spread and four denominations— Calvinism , Lutheranism , Unitarianism , and Roman Catholicism—were officially acknowledged in 1568. The Romanians' Orthodox faith remained only tolerated, although they made up more than one-third of the population, according to 17th-century estimations. The princes of Transylvania, Wallachia, and Moldavia joined
2896-462: A novel type of metal-halide perovskite material consisting of Au and Au cations in its crystal structure has been found. It has been shown to be unexpectedly stable at normal conditions. Gold pentafluoride , along with its derivative anion, AuF − 6 , and its difluorine complex , gold heptafluoride , is the sole example of gold(V), the highest verified oxidation state. Some gold compounds exhibit aurophilic bonding , which describes
3077-516: A policy of total reimbursement of the foreign debt by imposing austerity steps that impoverished the population and exhausted the economy. The process succeeded in repaying all of Romania's foreign government debt in 1989. At the same time, Ceaușescu greatly extended the authority of the Securitate secret police and imposed a severe cult of personality , which led to a dramatic decrease in the dictator's popularity and culminated in his overthrow in
3258-561: A political crisis in 2012. Near the end of 2013, The Economist reported Romania again enjoying "booming" economic growth at 4.1% that year, with wages rising fast and a lower unemployment than in Britain. Economic growth accelerated in the midst of government liberalisation in opening up new sectors to competition and investment—most notably, energy and telecoms. In 2016, the Human Development Index ranked Romania as
3439-620: A principle was enacted, but women could not vote or be candidates. Calypso Botez established the National Council of Romanian Women to promote feminist ideas. Romania was a multiethnic country, with ethnic minorities making up about 30% of the population, but the new constitution declared it a unitary national state in 1923. Although minorities could establish their own schools, Romanian language, history and geography could only be taught in Romanian. Agriculture remained
3620-422: A region often sees a flood of resources and development, which lasts as long as the mines are economic. When goldfields begin to decline in production, local economies find themselves destabilised and overly reliant upon an industry that will inevitably abandon the region when gold deposits are sufficiently depleted; leaving the areas without proper rehabilitation. Gold Gold is a chemical element with
3801-745: A regular tribute to the Ottoman sultans from 1417 and 1456, respectively. A military commander of Romanian origin, John Hunyadi , organised the defence of the Kingdom of Hungary until his death in 1456. Increasing taxes outraged the Transylvanian peasants, and they rose up in an open rebellion in 1437, but the Hungarian nobles and the heads of the Saxon and Székely communities jointly suppressed their revolt. The formal alliance of
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#17327930934793982-602: A result of Hungarian oppression in the region. In April 1990, a sit-in protest contesting the results of that year's legislative elections and accusing the FSN, including Iliescu, of being made up of former Communists and members of the Securitate grew rapidly to become what was called the Golaniad . Peaceful demonstrations degenerated into violence, prompting the intervention of coal miners summoned by Iliescu. This episode has been documented widely by both local and foreign media, and
4163-401: A sheet of 1 square metre (11 sq ft), and an avoirdupois ounce into 28 square metres (300 sq ft). Gold leaf can be beaten thin enough to become semi-transparent. The transmitted light appears greenish-blue because gold strongly reflects yellow and red. Such semi-transparent sheets also strongly reflect infrared light, making them useful as infrared (radiant heat) shields in
4344-533: A significant improvement in living standards as the country successfully reduced domestic poverty and established a functional democratic state. However, Romania's development suffered a major setback during the late 2000s' recession leading to a large gross domestic product contraction and a budget deficit in 2009. This led to Romania borrowing from the International Monetary Fund. Worsening economic conditions led to unrest and triggered
4525-423: A soluble tetrachloroaurate anion . Gold is insoluble in nitric acid alone, which dissolves silver and base metals , a property long used to refine gold and confirm the presence of gold in metallic substances, giving rise to the term ' acid test '. Gold dissolves in alkaline solutions of cyanide , which are used in mining and electroplating . Gold also dissolves in mercury , forming amalgam alloys, and as
4706-520: A solution of Au(OH) 3 in concentrated H 2 SO 4 produces red crystals of gold(II) sulfate , Au 2 (SO 4 ) 2 . Originally thought to be a mixed-valence compound, it has been shown to contain Au 4+ 2 cations, analogous to the better-known mercury(I) ion, Hg 2+ 2 . A gold(II) complex, the tetraxenonogold(II) cation, which contains xenon as a ligand, occurs in [AuXe 4 ](Sb 2 F 11 ) 2 . In September 2023,
4887-471: A successful Soviet offensive, the young King Michael I ordered Antonescu's arrest and appointed politicians from the National Democratic Bloc to form a new government on 23 August 1944. Romania switched sides during the war, and nearly 250,000 Romanian troops joined the Red Army's military campaign against Hungary and Germany, but Joseph Stalin regarded the country as an occupied territory within
5068-470: Is Au with a half-life of 2.27 days. Gold's least stable isomer is Au with a half-life of only 7 ns. Au has three decay paths: β decay, isomeric transition , and alpha decay. No other isomer or isotope of gold has three decay paths. The possible 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,
5249-696: Is Au , which decays by proton emission with a half-life of 30 μs. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission , α decay , and β decay . The exceptions are Au , which decays by electron capture, and Au , which decays most often by electron capture (93%) with a minor β decay path (7%). All of gold's radioisotopes with atomic masses above 197 decay by β decay. At least 32 nuclear isomers have also been characterized, ranging in atomic mass from 170 to 200. Within that range, only Au , Au , Au , Au , and Au do not have isomers. Gold's most stable isomer
5430-416: Is a cyanide extraction method, or gold cyanidation, introduced in the late 1800s. This a metallurgical technique used to extract gold from lower grade ores by converting gold into a water-soluble coordination complex. Finely ground rock is treated with a solution of sodium cyanide . The extract is absorbed onto carbon and then removed from the carbon with a solution of caustic soda and cyanide. Gold cyanide
5611-426: Is a method of extracting gold from alluvial deposits such as sand, gravel, and sediment. These are known as placer deposits which are typically found in riverbeds, stream beds, and floodplains. These deposits typically contain minerals that are resistant to weathering and eroision like gold , platinum , diamonds , and more. They are characterized by their relatively high concentration of valuable minerals compared to
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5792-648: Is also known, an example of a mixed-valence complex . Gold does not react with oxygen at any temperature and, up to 100 °C, is resistant to attack from ozone: Au + O 2 ⟶ ( no reaction ) {\displaystyle {\ce {Au + O2 ->}}({\text{no reaction}})} Au + O 3 → t < 100 ∘ C ( no reaction ) {\displaystyle {\ce {Au{}+O3->[{} \atop {t<100^{\circ }{\text{C}}}]}}({\text{no reaction}})} Some free halogens react to form
5973-520: Is also used in infrared shielding, the production of colored glass , gold leafing , and tooth restoration . Certain gold salts are still used as anti-inflammatory agents in medicine. Gold is the most malleable of all metals. It can be drawn into a wire of single-atom width, and then stretched considerably before it breaks. Such nanowires distort via the formation, reorientation, and migration of dislocations and crystal twins without noticeable hardening. A single gram of gold can be beaten into
6154-427: Is always richer at the exposed surface of gold-bearing veins, owing to the oxidation of accompanying minerals followed by weathering; and by 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
6335-517: Is attributed to wind-blown dust or rivers. At 10 parts per quadrillion, the Earth's oceans would hold 15,000 tonnes of gold. These figures are three orders of magnitude less than reported in the literature prior to 1988, indicating contamination problems with the earlier data. 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
6516-470: Is characterized by its low cost, as each rock is moved only once. It also has low environmental impact, as no stripping of vegetation or overburden is necessary, and all process water is fully recycled. Such operations are typical on New Zealand's South Island and in the Klondike region of Canada. Also called a cradle, a rocker box uses riffles located in a high-walled box to trap gold in a similar manner to
6697-612: Is done by small-scale miners using suction dredges. These are small machines that float on the water and are usually operated by one or two people. A suction dredge consists of a sluice box supported by pontoons, attached to a suction hose which is controlled by a miner working beneath the water. This method is particularly popular in areas where gold is found at river bottoms or submerge deposits . Suction dredging can have environmental impacts, moreso on aquatic habitats and water quality. Regulations and best practices are often in place to minimize these impacts. State dredging permits in many of
6878-434: Is essentially a man made channel with riffles set in the bottom. The riffles are designed to create dead zones in the current to allow gold to drop out of suspension. The box is placed in the stream to channel water flow. Gold-bearing material is placed at the top of the box. The material is carried by the current through the volt where gold and other dense material settles out behind the riffles. Less dense material flows out of
7059-752: Is estimated that the total gold production in Karnataka to date is 1000 tons. The mining of the Hungarian deposit (present-day Slovakia) primarily around Kremnica was the largest of the Medieval period in Europe. In South America, gold mining in the Andes dates back to thousands of years, with the Inca empire employing extensive gold mining operations in regions such as present-day Peru and Ecuador . They used stone tools and simple mining techniques to extract gold from rivers, streams, and surface deposits. During
7240-643: Is first attested in the 16th century by Italian humanists travelling in Transylvania , Moldavia , and Wallachia . The oldest known surviving document written in Romanian that can be precisely dated, a 1521 letter known as the " Letter of Neacșu from Câmpulung ", is notable for including the first documented occurrence of Romanian in a country name: Wallachia is mentioned as Țara Rumânească . Human remains found in Peștera cu Oase ("Cave with Bones"), radiocarbon date from circa 40,000 years ago, and represent
7421-470: Is found in ores in rock formed from the Precambrian time onward. It most often occurs as a native metal , typically in a metal solid solution with silver (i.e. as a gold/silver alloy ). Such alloys usually have a silver content of 8–10%. Electrum is elemental gold with more than 20% silver, and is commonly known as white gold . Electrum's color runs from golden-silvery to silvery, dependent upon
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7602-472: Is most often called the oldest since this treasure is the largest and most diverse. Gold artifacts 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 the start of the fourth, and smelting was developed during the course of the 4th millennium; gold artifacts appear in the archeology of Lower Mesopotamia during
7783-542: Is now questioned. The gold-bearing Witwatersrand rocks were laid down between 700 and 950 million years before the Vredefort impact. These gold-bearing rocks had furthermore been covered by a thick layer of Ventersdorp lavas and the Transvaal Supergroup of rocks before the meteor struck, and thus the gold did not actually arrive in the asteroid/meteorite. What the Vredefort impact achieved, however,
7964-960: Is produced by major corporations, there are an estimated 10 to 15 million small-scale artisanal gold miners worldwide. Around 4.5 million of them are women, and an estimated 600,000 children work in illegal artisanal gold mines. Artisanal miners use rudimentary methods to extract and process gold. Many of these people are mining to escape extreme poverty , unemployment and landlessness . In Ghana, galamsey miners are estimated to number 20,000 to 50,000. In neighboring francophone countries, such workers are called orpailleurs . In Brazil, Venezuela, Suriname, and French Guiana, workers are called garimpeiros . These workers are not required to claim responsibility for their social and environmental impacts. Miners risk government persecution, mine shaft collapses, and toxic poisoning from unsafe chemicals used in processing, such as mercury. For example, in Ghana during 2009,
8145-427: Is red if the particles are small; larger particles of colloidal gold are blue. Gold has only one stable isotope , Au , which is also its only naturally occurring isotope, so gold is both a mononuclidic and monoisotopic element . Thirty-six radioisotopes have been synthesized, ranging in atomic mass from 169 to 205. The most stable of these is Au with a half-life of 186.1 days. The least stable
8326-724: Is remembered as the June 1990 Mineriad . The subsequent disintegration of the Front produced several political parties, including most notably the Social Democratic Party (PDSR then PSD) and the Democratic Party (PD and subsequently PDL). The former governed Romania from 1990 until 1996 through several coalitions and governments, with Ion Iliescu as head of state. Since then, there have been several other democratic changes of government: in 1996 Emil Constantinescu
8507-484: 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. Common oxidation states of gold include +1 (gold(I) or aurous compounds) and +3 (gold(III) or auric compounds). Gold ions in solution are readily reduced and precipitated as metal by adding any other metal as
8688-589: Is the soluble form of gold encountered in mining. The binary gold halides , such as AuCl , form zigzag polymeric chains, again featuring linear coordination at Au. Most drugs based on gold are Au(I) derivatives. Au(III) (referred to as auric) is a common oxidation state, and is illustrated by gold(III) chloride , Au 2 Cl 6 . The gold atom centers in Au(III) complexes, like other d compounds, are typically square planar , with chemical bonds that have both covalent and ionic character. Gold(I,III) chloride
8869-629: Is then converted to relatively pure gold through gold parting . There are many environmental hazards associated with this extraction method, largely due to the high toxicity of the cyanide compounds. Furthermore, there are potentials for accidental spills or leaks to cause harm to aquatic ecosystems and human health. For example, in 2000, the Baia Mare cyanide spill in northern Romania released approximately 100,000 cubic metres (3,500,000 cu ft) of waste water contaminated with heavy metal sludge and up to 120 long tons (122 t) of cyanide into
9050-657: Is thought to have been delivered to Earth by asteroid impacts during the Late Heavy Bombardment , about 4 billion years ago. Gold which is reachable by humans has, in one case, been associated with a particular asteroid impact. The asteroid that formed Vredefort impact structure 2.020 billion years ago is often credited with seeding the Witwatersrand basin in South Africa with the richest gold deposits on earth. However, this scenario
9231-511: 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. Traditionally, gold in the universe 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
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#17327930934799412-416: Is unaffected by most acids. 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 1:3 mixture of nitric acid and hydrochloric acid . Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable in the pure acid because of the chemical equilibrium of
9593-619: Is well documented from the end of the 11th century. Scholars who reject the Daco-Roman continuity theory say that the first Vlach groups left their Balkan homeland for the mountain pastures of the eastern and southern Carpathians in the 11th century, establishing the Romanians' presence in the lands to the north of the Lower Danube. Exposed to nomadic incursions, Transylvania developed into an important border province of
9774-614: The 2008 summit in Bucharest. The country applied in June 1993 for membership in the European Union and became an Associated State of the EU in 1995, an Acceding Country in 2004, and a full member on 1 January 2007. During the 2000s, Romania had one of the highest economic growth rates in Europe and has been referred at times as "the Tiger of Eastern Europe". This has been accompanied by
9955-815: The Arab countries and the Palestine Liberation Organization (PLO) allowed Romania to play a key role in the Israel– Egypt and Israel–PLO peace talks. As Romania's foreign debt increased sharply between 1977 and 1981 (from US$ 3 billion to $ 10 billion), the influence of international financial organisations—such as the International Monetary Fund (IMF) and the World Bank —grew, gradually conflicting with Ceaușescu's autocratic rule. He eventually initiated
10136-633: The British royal family . During the 19th century, numerous gold rushes in remote regions around the globe caused large migrations of miners, such as the California Gold Rush of 1849. This is one of the most famous gold rushes in history. The discovery of gold at Sutter's Mill in California sparked a massive migration of people from around the world to California in search of gold. The rush significantly accelerated westward expansion in
10317-666: 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 106 AD onwards. One of their largest mines was at Las Medulas in León , where seven long aqueducts enabled them to sluice most of
10498-793: The Danubian Principalities ) in 1774. Taking advantage of the Greek War of Independence , a Wallachian lesser nobleman, Tudor Vladimirescu, stirred up a revolt against the Ottomans in January ;1821, but he was murdered in June by Phanariot Greeks. After a new Russo-Turkish War , the Treaty of Adrianople strengthened the autonomy of the Danubian Principalities in 1829, although it also acknowledged
10679-576: The Dompoase mine collapse killed 18 workers. It was the worst mining disaster in Ghanaian history. Children in these mines suffer extremely harsh working conditions and various hazards such as collapsing tunnels, explosions, and chemical exposure. Children may be especially vulnerable to these hazards and many suffer from serious respiratory conditions, hearing, and vision problems. Gold mining by large multi-national corporations produces about 80% of
10860-694: The Holy League against the Ottoman Empire in 1594. The Wallachian prince, Michael the Brave , united the three principalities under his rule in May ;1600. The neighboring powers forced him to abdicate in September, but he became a symbol of the unification of the Romanian lands in the 19th century. Although the rulers of the three principalities continued to pay tribute to the Ottomans,
11041-594: The Kingdom of Hungary . The Székelys—a community of free warriors—settled in central Transylvania around 1100 and moved to the easternmost regions around 1200. Colonists from the Holy Roman Empire —the Transylvanian Saxons ' ancestors—came to the province in the 1150s. A high-ranking royal official, styled voivode , ruled the Transylvanian counties from the 1170s, but
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#173279309347911222-689: The Kolar gold fields was mined to a depth of 50 metres (160 ft) during the Gupta period in the fifth century AD. During the Chola period in the 9th and 10th century AD, the scale of the operation grew. The metal continued to be mined by the eleventh century kings of South India, the Vijayanagara Empire from 1336 to 1560, and later by Tipu Sultan , the king of Mysore state and the British. It
11403-586: The Old Kingdom , the oval mallet was introduced for mining. By the Middle Kingdom , stone mortars to process ores and a new gold-washing technique were introduced. During the New Kingdom , Nubian mining expanded under Egyptian occupation with the invention of the grinding mill . Additionally, gold was associated with the sun god Ra and was believed to be eternal and indestructible, symbolising
11584-424: The Old Testament , starting with Genesis 2:11 (at Havilah ), the story of the golden calf , and many parts of the temple including the Menorah and the golden altar. In the New Testament , it is included with the gifts of the magi in the first chapters of Matthew. The Book of Revelation 21:21 describes the city of New Jerusalem as having streets "made of pure gold, clear as crystal". Exploitation of gold in
11765-423: The Republic of Genoa started establishing colonies on the Black Sea, including Calafat , and Constanța . The Mongols destroyed large territories during their invasion of Eastern and Central Europe in 1241 and 1242. The Mongols' Golden Horde emerged as the dominant power of Eastern Europe, but Béla IV of Hungary's land grant to the Knights Hospitallers in Oltenia and Muntenia shows that
11946-455: The Tisza River. Historically, mercury was used extensively in placer gold mining in order to form mercury-gold amalgam with smaller gold particles, and thereby increase the gold recovery rates. First, the gold ore is crushed and ground to a fine powder to expose the gold particles for amalgamation. Then, this finely ground ore is mixed with liquid mercury to amalgamate it. Mercury forms an amalgam, an alloy, with gold particles to allow for
12127-440: The Tripartite Pact of Germany, Italy and Japan on 23 November. The Iron Guard staged a coup against Antonescu, but he crushed the riot with German support and introduced a military dictatorship in early 1941. Romania entered World War II soon after the German invasion of the Soviet Union in June 1941. The country regained Bessarabia and Northern Bukovina, and the Germans placed Transnistria (the territory between
12308-483: The Varna Necropolis near Lake Varna and the Black Sea coast, thought to be the earliest "well-dated" finding of gold artifacts in history. Several prehistoric Bulgarian finds are considered no less old – the golden treasures of Hotnitsa, Durankulak , artifacts from the Kurgan settlement of Yunatsite near Pazardzhik , the golden treasure Sakar, as well as beads and gold jewelry found in the Kurgan settlement of Provadia – Solnitsata ("salt pit"). However, Varna gold
12489-567: The chemical symbol Au (from Latin aurum ) and atomic number 79. In its pure form, it is a bright , slightly orange-yellow, dense, soft, malleable , and ductile metal . Chemically, gold is a transition metal , a group 11 element , and one of the noble metals . It is one of the least reactive chemical elements, being the second-lowest in the reactivity series . It is solid under standard conditions . Gold often occurs in free elemental ( native state ), as nuggets or grains, in rocks , veins , and alluvial deposits . It occurs in
12670-478: The first constitution of Romania in the same year. The Great Powers acknowledged Romania's full independence at the Congress of Berlin and Carol I was crowned king in 1881. The Congress also granted the Danube Delta and Dobruja to Romania. Although Romanian scholars strove for the unification of all Romanians into a Greater Romania , the government did not openly support their irredentist projects. The Transylvanian Romanians and Saxons wanted to maintain
12851-413: The national flag . In Transylvania, most Romanians supported the imperial government against the Hungarian revolutionaries after the Diet passed a law concerning the union of Transylvania and Hungary. Bishop Andrei Șaguna proposed the unification of the Romanians of the Habsburg Monarchy in a separate duchy, but the central government refused to change the internal borders. The Treaty of Paris put
13032-470: 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. Less common oxidation states of gold include −1, +2, and +5. The −1 oxidation state occurs in aurides, compounds containing the Au anion . Caesium auride (CsAu), for example, crystallizes in the caesium chloride motif; rubidium, potassium, and tetramethylammonium aurides are also known. Gold has
13213-401: The 1930s. The democratic parties were squeezed between conflicts with the fascist and anti-Semitic Iron Guard and the authoritarian tendencies of King Carol II . The King promulgated a new constitution and dissolved the political parties in 1938, replacing the parliamentary system with a royal dictatorship. The 1938 Munich Agreement convinced King Carol II that France and
13394-544: The 3rd or 4th millennium BC, may be the world's oldest known gold mine. Gold has been prized by humans since prehistoric times. Archaeological evidence suggests that humans were mining gold as far back as 4000 BCE, with some the earliest known gold artifacts dating back to ancient Mesopotamia . Particularly in the region of present-day Iraq, gold was mined extensively. The ancient Sumerians , around 2500 BCE, developed sophisticated techniques for extracting gold from alluvial deposits and underground mines. These techniques included
13575-570: The Amazon rainforest, Indigenous peoples have been killed and had their rightfully owned land stolen from them. As a consequence of this, some have left the rainforest to move to cities which further puts them at risk to disease, homelessness, and poverty. Artisanal gold mining is widespread across Africa , occurring in numerous countries including Ghana , Mali , Burkina Faso , Tanzania , Zimbabwe , and many others. For many individuals and communities in rural Africa, artisanal gold mining represents
13756-531: The Bulgar elite had already begun in the 9th century. Following the conquest of southern Transylvania around 830, people from the Bulgar Empire mined salt at the local salt mines. The Council of Preslav declared Old Church Slavonic the language of liturgy in the country in 893. The Vlachs also adopted Old Church Slavonic as their liturgical language. The Magyars (or Hungarians) took control of
13937-635: The Cucuteni–Trypillia culture built the largest settlements in Neolithic Europe , some of which contained as many as three thousand structures and were possibly inhabited by 20,000 to 46,000 people. The first fortified settlements appeared around 1800 BC, showing the militant character of Bronze Age societies. Greek colonies established on the Black Sea coast in the 7th century BC became important centres of commerce with
14118-631: The Danubian Principalities under the collective guardianship of the Great Powers in 1856. After special assemblies convoked in Moldavia and Wallachia urged the unification of the two principalities , the Great Powers did not prevent the election of Alexandru Ioan Cuza as their collective domnitor (or ruling prince) in January 1859. The united principalities officially adopted
14299-665: The European Pontic steppe , occupied the Lower Danube region in 680. After the Avar Khaganate collapsed in the 790s, the First Bulgarian Empire became the dominant power of the region, occupying lands as far as the river Tisa . The First Bulgarian Empire had a mixed population consisting of the Bulgar conquerors, Slavs , and Vlachs (or Romanians) but the Slavicisation of
14480-631: The European Union, primarily driven by the service sector . Romania is a net exporter of cars and electric energy worldwide, and its citizens benefit from some of the fastest internet speeds globally . Romania is a member of several international organizations , including the European Union , NATO , and the BSEC . "Romania" derives from the local name for Romanian ( Romanian : român ), which in turn derives from Latin romanus , meaning " Roman " or "of Rome ". This ethnonym for Romanians
14661-467: The Highlands during the 16th and 17th century. Gold deposits were discovered in rivers and streams, leading to a surge in prospecting and mining activity. The Scottish Crown took an interest in gold discoveries, in hopes of aiding the kingdom's economy and revenue. King James IV of Scotland established a royal mint to produce gold coins from Scottish gold. The Scottish gold rush eventually waned due to
14842-580: The Hungarian, Saxon, and Székely leaders, known as the Union of the Three Nations , became an important element of the self-government of Transylvania. The Orthodox Romanian knezes ("chiefs") were excluded from the Union. The Kingdom of Hungary collapsed, and the Ottomans occupied parts of Banat and Crișana in 1541. Transylvania and Maramureș , along with the rest of Banat and Crișana developed into
15023-673: The Klondike River by George Carmack and his Indigenous companions, Skookum Jim Mason and Tagish Charlie . As prospectors arrived in Klondike, makeshift towns and settlements sprang up along the rivers, including Dawson City , which because the largest town in Yukon at the height of the gold rush. Prospectors employed various mining techniques to extract gold from the Klondike's streams and riverbeds, including placer mining, dredging, and hydraulic mining. The Carlin Trend of Nevada, U.S.,
15204-896: The Middle Ages, Europe experience several gold rushes. Most notably in regions like Transylvania, Scotland, and Wales. These rushes were often small-scale and localised compared to later rushes in history. The Transylvania gold rush took place in the Kingdom of Hungary (present-day Romania ), primarily in the region of Transylvania during the medieval period. Transylvania was known for its rich mineral resources including gold, silver, and other metals. Miners in Transylvania used both surface and underground mining techniques to extract gold from alluvial deposits and veins. These methods include panning, sluicing, and rudimentary shaft mining. The Scottish gold rush occurred in Scotland, primarily in
15385-631: The Orthodox Romanian prelates to accept the union with the Roman Catholic Church in 1699. The Church Union strengthened the Romanian intellectuals' devotion to their Roman heritage. The Orthodox Church was restored in Transylvania only after Orthodox monks stirred up revolts in 1744 and 1759. The organisation of the Transylvanian Military Frontier caused further disturbances, especially among
15566-622: The Romanian army on behalf of the Entente Powers a day before Germany capitulated on 11 November 1918. Austria-Hungary quickly disintegrated after the war. The General Congress of Bukovina proclaimed the union of the province with Romania on 28 November 1918, and the Grand National Assembly proclaimed the union of Transylvania, Banat, Crișana and Maramureș with the kingdom on 1 December. Peace treaties with Austria, Bulgaria and Hungary delineated
15747-590: The Romanians as the fourth privileged nation was forced into exile. Uniate and Orthodox clerics and laymen jointly signed a plea for the Transylvanian Romanians' emancipation in 1791, but the monarch and the local authorities refused to grant their requests. The Treaty of Küçük Kaynarca authorised the Russian ambassador in Istanbul to defend the autonomy of Moldavia and Wallachia (known as
15928-795: The Romans invaded Transylvania in what is now modern Romania in the second century AD. The legions were led by the emperor Trajan, and their exploits are shown on Trajan's Column in Rome and the several reproductions of the column elsewhere (such as the Victoria and Albert Museum in London ). Under the Eastern Roman Empire Emperor Justinian's rule, gold was mined in the Balkans, Anatolia, Armenia, Egypt, and Nubia. In
16109-616: The September 1943 Allied armistice with Italy , Romania became the second Axis power in Europe in 1943–1944. After the German occupation of Hungary in March 1944, about 132,000 Jews – mainly Hungarian-speaking – were deported to extermination camps from Northern Transylvania with the Hungarian authorities' support. After the Soviet victory in the Battle of Stalingrad in 1943, Iuliu Maniu ,
16290-450: The Soviet Union on 26 June 1940, Northern Transylvania to Hungary on 30 August, and Southern Dobruja to Bulgaria in September. After the territorial losses, the King was forced to abdicate in favour of his minor son, Michael I , on 6 September, and Romania was transformed into a national-legionary state under the leadership of General Ion Antonescu . Antonescu signed
16471-612: The Soviet sphere of influence. Stalin's deputy instructed the King to make the Communists' candidate, Petru Groza , the prime minister in March 1945. The Romanian administration in Northern Transylvania was soon restored, and Groza's government carried out an agrarian reform. In February 1947, the Paris Peace Treaties confirmed the return of Northern Transylvania to Romania, but they also legalised
16652-474: The Soviet-led 1968 invasion of Czechoslovakia . Ceaușescu even publicly condemned the action as "a big mistake, [and] a serious danger to peace in Europe and to the fate of Communism in the world". It was the only Communist state to maintain diplomatic relations with Israel after 1967's Six-Day War and established diplomatic relations with West Germany the same year. At the same time, close ties with
16833-516: The Székely and Saxon seats (or districts) were not subject to the voivodes' authority. Royal charters wrote of the " Vlachs ' land" in southern Transylvania in the early 13th century, indicating the existence of autonomous Romanian communities . Papal correspondence mentions the activities of Orthodox prelates among the Romanians in Muntenia in the 1230s. Also in the 13th century,
17014-708: The Székelys in 1764 . Princes Dimitrie Cantemir of Moldavia and Constantin Brâncoveanu of Wallachia concluded alliances with the Habsburg Monarchy and Russia against the Ottomans, but they were dethroned in 1711 and 1714, respectively. The sultans lost confidence in the native princes and appointed Orthodox merchants from the Phanar district of Istanbul to rule Moldova and Wallachia. The Phanariot princes pursued oppressive fiscal policies and dissolved
17195-473: The United Kingdom could not defend Romanian interests. German preparations for a new war required the regular supply of Romanian oil and agricultural products. The two countries concluded a treaty concerning the coordination of their economic policies in 1939, but the King could not persuade Adolf Hitler to guarantee Romania's frontiers. Romania was forced to cede Bessarabia and Northern Bukovina to
17376-599: The United States and had profound effects on the region's economy and society. The gold rushes began in 1851 when Edward Hargraves , a prospector, discovered gold near Bathhurst , New South Wales . The most well known gold rush in Australia was the Victorian Gold Rush . Thousands of people, known as 'diggers', came from around the world to Australia in search of gold, which ultimately contributed to
17557-484: The United States gold dredging areas specify a seasonal time period and area closures to avoid conflicts between dredgers and the spawning time of fish populations. Some US states, such as Montana, require an extensive permitting procedure, including permits. Some large suction dredges [100 horsepower (75 kW) & 250 mm (10 in)] are used in commercial production throughout the world. Small suction dredges are much more efficient at extracting smaller gold than
17738-642: The area of the Kolar Gold Fields in Bangarpet Taluk , Kolar district of Karnataka state, India; gold was first mined prior to the 2nd and 3rd century AD by digging small pits. Golden objects found in Harappa and Mohenjo-daro have been traced to Kolar through the analysis of impurities – the impurities include 11% silver concentration, found only in KGF ore.The Champion reef at
17919-611: The army. The neighboring powers took advantage of the situation: the Habsburg Monarchy annexed the northwestern part of Moldavia, or Bukovina , in 1775, and the Russian Empire seized the eastern half of Moldavia, or Bessarabia , in 1812. A census revealed that the Romanians were more numerous than any other ethnic group in Transylvania in 1733, but legislation continued to use contemptuous adjectives (such as "tolerated" and "admitted") when referring to them. The Uniate bishop , Inocențiu Micu-Klein who demanded recognition of
18100-576: The box as tailings . Larger commercial placer mining operations employ screening plants, or trommels , to remove the larger alluvial materials such as boulders and gravel, before concentrating the remainder in a sluice box or jig plant. After the gold is sorted through trommels, it is then placed through regular sluice boxes for further sorting. These operations typically include diesel powered, earth moving equipment including excavators, bulldozers, wheel loaders , and rock trucks. Although this method has largely been replaced by modern methods, some dredging
18281-1409: The corresponding gold halides. Gold is strongly attacked by fluorine at dull-red heat to form gold(III) fluoride AuF 3 . Powdered gold reacts with chlorine at 180 °C to form gold(III) chloride AuCl 3 . Gold reacts with bromine at 140 °C to form a combination of gold(III) bromide AuBr 3 and gold(I) bromide AuBr, but reacts very slowly with iodine to form gold(I) iodide AuI: 2 Au + 3 F 2 → Δ 2 AuF 3 {\displaystyle {\ce {2Au{}+3F2->[{} \atop \Delta ]2AuF3}}} 2 Au + 3 Cl 2 → Δ 2 AuCl 3 {\displaystyle {\ce {2Au{}+3Cl2->[{} \atop \Delta ]2AuCl3}}} 2 Au + 2 Br 2 → Δ AuBr 3 + AuBr {\displaystyle {\ce {2Au{}+2Br2->[{} \atop \Delta ]AuBr3{}+AuBr}}} 2 Au + I 2 → Δ 2 AuI {\displaystyle {\ce {2Au{}+I2->[{} \atop \Delta ]2AuI}}} Gold does not react with sulfur directly, but gold(III) sulfide can be made by passing hydrogen sulfide through
18462-493: The country and proclaimed Romania a people's republic . Romania remained under the direct military occupation and economic control of the USSR until the late 1950s. During this period, Romania's vast natural resources were drained continuously by mixed Soviet-Romanian companies ( SovRoms ) set up for unilateral exploitative purposes. In 1948, the state began to nationalise private firms and to collectivise agriculture. Until
18643-424: The densest element, osmium , is 22.588 ± 0.015 g/cm . Whereas most metals are gray or silvery white, gold is slightly reddish-yellow. 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. Similar effects impart
18824-599: The early 1960s, the government severely curtailed political liberties and vigorously suppressed any dissent with the help of the Securitate —the Romanian secret police. During this period the regime launched several campaigns of purges during which numerous " enemies of the state " and "parasite elements" were targeted for different forms of punishment including: deportation, internal exile, internment in forced labour camps and prisons—sometimes for life—as well as extrajudicial killing . Nevertheless, anti-communist resistance
19005-689: The early 4th millennium. As of 1990, gold artifacts found at the Wadi Qana cave cemetery of the 4th millennium BC in West Bank were the earliest from the Levant. Gold artifacts such as the golden hats and the Nebra disk appeared in Central Europe from the 2nd millennium BC Bronze Age . The oldest known map of a gold mine was drawn in the 19th Dynasty of Ancient Egypt (1320–1200 BC), whereas
19186-567: The early 7th century. The Goths were expanding towards the Lower Danube from the 230s, forcing the native peoples to flee to the Roman Empire or to accept their suzerainty . The Goths' rule ended abruptly when the Huns invaded their territory in 376, causing new waves of migrations. The Huns forced the remnants of the local population into submission, but their empire collapsed in 454. The Gepids took possession of
19367-427: The efficient capture of gold from the ore. The gold is concentrated by boiling away the mercury from the amalgam . This process is called retorting. This is effective in extracting very small gold particles, but the process is hazardous due to the toxicity of mercury vapour. Large-scale use of mercury stopped in the 1960s. However, mercury is still used in artisanal and small-scale gold mining (ASGM). While most gold
19548-414: The evacuation of the province Dacia Trajana in the 270s. Scholars supporting the continuity theory are convinced that most Latin-speaking commoners stayed behind when the army and civil administration were withdrawn. The Romans did not abandon their fortresses along the northern banks of the Lower Danube for decades, and Dobruja (known as Scythia Minor ) remained an integral part of the Roman Empire until
19729-751: The extraction process. This pollution can have detrimental effects on aquatic ecosystems and human health. Soil degradation has also been found to be impacted by gold mining. Mining activities can disturb soil structure, leading to erosion, sedimentation of waterways, and loss of fertile land for agriculture or vegetation regrowth. More evidently, dust and emissions from mining machiner and processing facilities can contribute to air pollution, impacting air quality and potentially causings respiratory problems for nearby communities. Large-scale gold mining projects may require land acquisition and resettlement of local communities, leading to displacement, loss of livelihoods, and disruption of traditional ways of life. In addition to
19910-468: The fact that most of the former industrial and economic enterprises which were built and operated during the communist period were closed, mainly as a result of the policies of privatisation of the post–1989 regimes. Corruption has been a major issue in contemporary Romanian politics. In November 2015, massive anti-corruption protests which developed in the wake of the Colectiv nightclub fire led to
20091-610: The federalisation of Austria-Hungary and the Romanian intellectuals established a cultural association to promote the use of Romanian. Fearing Russian expansionism, Romania secretly joined the Triple Alliance of Germany, Austria-Hungary, and Italy in 1883, but public opinion remained hostile to Austria-Hungary. Romania seized Southern Dobruja from Bulgaria in the Second Balkan War in 1913. German and Austrian-Hungarian diplomacy supported Bulgaria during
20272-467: The first century AD. Romania – in Europe (green & dark grey) – in the European Union (green) Romania is a country located at the crossroads of Eastern and Southeast Europe . It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to the east, and the Black Sea to the southeast. It has
20453-591: The first written reference to gold was recorded in the 12th Dynasty around 1900 BC. Egyptian hieroglyphs from as early as 2600 BC describe gold, which King Tushratta of the Mitanni claimed was "more plentiful than dirt" in Egypt. Egypt and especially Nubia had the resources to make them major gold-producing areas for much of history. One of the earliest known maps, known as the Turin Papyrus Map , shows
20634-524: The former Dacia province. Place names that are of Slavic origin abound in Romania, indicating that a significant Slavic-speaking population lived in the territory. The first Slavic groups settled in Moldavia and Wallachia in the 6th century, in Transylvania around 600. The nomadic Avars defeated the Gepids and established a powerful empire around 570. The Bulgars , who also came from
20815-403: The gold acts simply as a solute, this is not a chemical reaction . A relatively rare element, gold is a precious metal that has been used for coinage , jewelry , and other works of art throughout recorded history . In the past, a gold standard was often implemented as a monetary policy . Gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard
20996-690: The gold supply. Most gold is mined in developing nations. Large mining companies play a key role in globalisation of the economy by linking rich and poor companies. Newmont and Barrick Gold are the largest gold mining companies in the world, but there are many smaller corporations in the industry. Local communities are frequently vulnerable to environmental degradation caused by large mining companies and may lack government protection or industry regulation. For example, thousands of people around Lega Dembi mine are exposed to mercury, arsenic, and other toxins resulting in widespread health problems and birth defects. Vulnerable communities may also lose their land to
21177-501: The growth of cities like Melbourne and Sydney . The discovery of gold in the Witwatersrand led to the Second Boer War and ultimately the founding of South Africa. This transformed the region into one of the wealthiest gold-producing areas in the world. This rush played a crucial role in the development of South Africa's economy and lead to the establishment of Johannesburg, known as the 'city of gold'. Gold-bearing reefs in
21358-764: The heat is unbearable for humans, and air conditioning is required for the safety of the workers. The first such mine to receive air conditioning was Robinson Deep , at that time the deepest mine in the world for any mineral. Gold is also produced by mining in which it is not the principal product. Large copper mines, such as the Bingham Canyon mine in Utah, often recover considerable amounts of gold and other metals along with copper. Sand and gravel pits, like those in Denver (Colorado), may recover small amounts of gold in their wash operations. The largest producing gold mine in
21539-563: The highest electron affinity of any metal, at 222.8 kJ/mol, making Au a stable species, analogous to the halides . Gold also has a –1 oxidation state in covalent complexes with the group 4 transition metals, such as in titanium tetraauride and the analogous zirconium and hafnium compounds. These chemicals are expected to form gold-bridged dimers in a manner similar to titanium(IV) hydride . Gold(II) compounds are usually diamagnetic with Au–Au bonds such as [ Au(CH 2 ) 2 P(C 6 H 5 ) 2 ] 2 Cl 2 . The evaporation of
21720-409: The local Vlach rulers were subject to the king's authority in 1247. Basarab I of Wallachia united the Romanian polities between the southern Carpathians and the Lower Danube in the 1310s. He defeated the Hungarian royal army in the Battle of Posada and secured the independence of Wallachia in 1330. The second Romanian principality, Moldavia , achieved full autonomy during
21901-647: The local chieftains and established Roman Catholic bishoprics (office of a bishop) in Transylvania and Banat in the early 11th century. Significant Pecheneg groups fled to the Byzantine Empire in the 1040s; the Oghuz Turks followed them, and the nomadic Cumans became the dominant power of the steppes in the 1060s. Cooperation between the Cumans and the Vlachs against the Byzantine Empire
22082-692: The local tribes. Among the native peoples, Herodotus listed the Getae of the Lower Danube region, the Agathyrsi of Transylvania and the Syginnae of the plains along the river Tisza at the beginning of the 5th century BC. Centuries later, Strabo associated the Getae with the Dacians who dominated the lands along the southern Carpathian Mountains in the 1st century BC. Burebista
22263-456: The lowest ever recorded for tropical forests, with there being little to no tree regeneration at abandoned mining camps, even after several years. The Amazon rainforest is at risk for 'savannization', which is the gradual transformation of a tropical rainforest into a savannah. This would ultimately lead to a collapse of biodiversity, ecosystems, and climate. Gold mining produces more waste than mining of other minerals, because it can be mined at
22444-655: The mine. Some large companies have attempted to build local legitimacy through corporate responsibility initiatives and local development. Gold mining can significantly alter the natural environment. Gold mining activities in tropical forests are increasingly causing deforestation along rivers and in remote areas rich in biodiversity. Mining has increased rainforest loss up to 70km beyond lease boundaries, causing nearly 11,670 km of deforestation between 2005 to 2015. Up to 9% of gold mining occurs outside of these regulated lease boundaries. Other gold mining impacts, particularly in aquatic systems with residual cyanide or mercury (used in
22625-547: The mineral quartz, and gold out of the fluids and onto nearby surfaces. The world's oceans contain gold. Measured concentrations of gold in the Atlantic and Northeast Pacific are 50–150 femtomol /L or 10–30 parts per quadrillion (about 10–30 g/km ). In general, gold concentrations for south Atlantic and central Pacific samples are the same (~50 femtomol/L) but less certain. Mediterranean deep waters contain slightly higher concentrations of gold (100–150 femtomol/L), which
22806-575: The most talented princes— Gabriel Bethlen of Transylvania, Matei Basarab of Wallachia, and Vasile Lupu of Moldavia—strengthened their autonomy. The united armies of the Holy League expelled the Ottoman troops from Central Europe between 1684 and 1699, and the Principality of Transylvania was integrated into the Habsburg monarchy . The Habsburgs supported the Catholic clergy and persuaded
22987-526: The name Romania on 21 February 1862. Cuza's government carried out a series of reforms, including the secularisation of the property of monasteries and agrarian reform, but a coalition of conservative and radical politicians forced him to abdicate in February ;1866. Cuza's successor, a German prince, Karl of Hohenzollern-Sigmaringen (or Carol I), was elected in May. The parliament adopted
23168-412: The neighbouring Free State province were found shortly thereafter, driving significant development in the region with the establishment of the Free State goldfields . Also known as the Yukon Gold Rush , brought prospectors from around the world to the Klondike region of the Yukon territory in Canada . The Klondike Gold Rush began in 1896, when gold was discovered in Bonanza Creek , a tributary of
23349-465: The new borders in 1919 and 1920, but the Soviet Union did not acknowledge the loss of Bessarabia. Romania achieved its greatest territorial extent, expanding from the pre-war 137,000 to 295,000 km (53,000 to 114,000 sq mi). A new electoral system granted voting rights to all adult male citizens, and a series of radical agrarian reforms transformed the country into a "nation of small landowners" between 1918 and 1921. Gender equality as
23530-411: The noble metals, it still forms many diverse compounds. The oxidation state of gold in its compounds ranges from −1 to +5, but Au(I) and Au(III) dominate its chemistry. Au(I), referred to as the aurous ion, is the most common oxidation state with soft ligands such as thioethers , thiolates , and organophosphines . Au(I) compounds are typically linear. A good example is Au(CN) − 2 , which
23711-468: The north to the southwest and include Moldoveanu Peak , at an altitude of 2,544 m (8,346 ft). Romania's capital and largest city is Bucharest . Other major urban centers include Cluj-Napoca , Timișoara , Iași , Constanța and Brașov . Settlement in the territory of modern Romania began in the Lower Paleolithic , later becoming the kingdom of Dacia before Roman conquest and Romanisation . The modern Romanian state emerged in 1859 through
23892-413: The old bucket line . This has improved the chances of finding gold. Smaller dredges with 50-to-100-millimetre (2 to 4 in) suction tubes are used to sample areas behind boulders and along potential pay streaks, until "colour" (gold) appears. Other larger scale dredging operations take place on exposed river gravel bars at seasonal low water. These operations typically use a land based excavator to feed
24073-728: The oldest known Homo sapiens in Europe. Neolithic agriculture spread after the arrival of a mixed group of people from Thessaly in the 6th millennium BC. Excavations near a salt spring at Lunca yielded the earliest evidence for salt exploitation in Europe; here salt production began between the 5th and 4th millennium BC. The first permanent settlements developed into "proto-cities", which were larger than 320 hectares (800 acres). The Cucuteni–Trypillia culture —the best known archaeological culture of Old Europe —flourished in Muntenia , southeastern Transylvania and northeastern Moldavia between c. 5500 to 2750 BC. During its middle phase (c. 4000 to 3500 BC), populations belonging to
24254-438: The oldest known gold artifacts were found in the Varna Necropolis in Bulgaria . The graves of the necropolis were built between 4700 and 4200 BC, indicating that gold mining could be at least 6,724 years old. During a series of excavations carried out between 1878 and 1992, several graves were found with more than 6kg of gold. A group of German and Georgian archaeologists claims the Sakdrisi site in southern Georgia , dating to
24435-405: The opinion polls. This surprise victory was attributed by many analysts to the implication of the Romanian diaspora in the voting process, with almost 50% casting their votes for Klaus Iohannis in the first round, compared to only 16% for Ponta. In 2019, Iohannis was re-elected president in a landslide victory over former Prime Minister Viorica Dăncilă . The post–1989 period is characterised by
24616-441: The pharoah's divine power and afterlife. Gold has also been found in the tombs of Tutankhamun and other pharoahs. During the Bronze Age, gold objects were also plentiful; especially in Ireland and Spain. Romans employed slave labour and used hydraulic mining methods, such as hushing and ground sluicing on a large scale to extract gold from extensive alluvial (loose sediment) deposits, such as those at Las Medulas . Mining
24797-418: 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
24978-684: The possible respiratory problems that could be acquired, individuals may be exposed to hazardous chemicals used in gold extraction such as mercury and cyanide. These chemicals pose risks to gold miners, communities, and wildlife; resulting in further medical problems involving neurological disorders and waterborne diseases . Gold mining in some regions has been associated with conflicts over land rights, labour rights violations, and exploitation of vulnerable populations, including Indigenous peoples and artisanal miners. Mining activities can damage or destroy cultural heritage sites, artifacts, and sacred areas; further impacting cultural identities and heritages. In
25159-544: The presence of units of the Red Army in the country. During the Soviet occupation of Romania , the communist-dominated government called for new elections in 1946, which they fraudulently won , with a fabricated 70% majority of the vote. Thus, they rapidly established themselves as the dominant political force. Gheorghe Gheorghiu-Dej , a communist party leader imprisoned in 1933, escaped in 1944 to become Romania's first communist leader. In February 1947, he and others forced King Michael I to abdicate and leave
25340-467: The principal sector of economy, but several branches of industry—especially the production of coal, oil, metals, synthetic rubber, explosives and cosmetics—developed during the interwar period . With oil production of 5.8 million tons in 1930, Romania ranked sixth in the world. Two parties, the National Liberal Party and the National Peasants' Party , dominated political life, but the Great Depression in Romania brought about significant changes in
25521-409: The project. The earliest recorded metal employed by humans appears to be gold, which can be found free or " native ". Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c. 40,000 BC . The oldest gold artifacts in the world are from Bulgaria and are dating back to the 5th millennium BC (4,600 BC to 4,200 BC), such as those found in
25702-516: The provincials enjoyed a long period of peace and prosperity in the 2nd century. Scholars accepting the Daco-Roman continuity theory—one of the main theories about the origin of the Romanians —say that the cohabitation of the native Dacians and the Roman colonists in Roman Dacia was the first phase of the Romanians' ethnogenesis . The Carpians , Goths , and other neighbouring tribes made regular raids against Dacia from the 210s. The Romans could not resist, and Emperor Aurelian ordered
25883-582: The r-process in the collision of neutron stars . In both cases, satellite spectrometers at first only indirectly detected the resulting gold. However, in August 2017, the spectroscopic signatures of heavy elements, including gold, were observed by electromagnetic observatories in the GW170817 neutron star merger event, after gravitational wave detectors confirmed the event as a neutron star merger. Current astrophysical models suggest that this single neutron star merger event generated between 3 and 13 Earth masses of gold. This amount, along with estimations of
26064-620: The rare bismuthide maldonite ( Au 2 Bi ) and antimonide aurostibite ( AuSb 2 ). Gold also occurs in rare alloys with copper , lead , and mercury : the minerals auricupride ( Cu 3 Au ), novodneprite ( AuPb 3 ) and weishanite ( (Au,Ag) 3 Hg 2 ). A 2004 research paper 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. A 2013 study has claimed water in faults vaporizes during an earthquake, depositing gold. When an earthquake strikes, it moves along
26245-420: The rate of occurrence of these neutron star merger events, suggests that such mergers may produce enough gold to account for most of the abundance of this element in the universe. Because the Earth was molten when it was formed , almost all of the gold present in the early Earth probably sank into the planetary core . Therefore, as hypothesized in one model, most of the gold in the Earth's crust and mantle
26426-935: The reaction. However, the ions are removed from the equilibrium by hydrochloric acid, forming AuCl − 4 ions, or chloroauric acid , thereby enabling further oxidation: 2 Au + 6 H 2 SeO 4 → 200 ∘ C Au 2 ( SeO 4 ) 3 + 3 H 2 SeO 3 + 3 H 2 O {\displaystyle {\ce {2Au{}+6H2SeO4->[{} \atop {200^{\circ }{\text{C}}}]Au2(SeO4)3{}+3H2SeO3{}+3H2O}}} Au + 4 HCl + HNO 3 ⟶ HAuCl 4 + NO ↑ + 2 H 2 O {\displaystyle {\ce {Au{}+4HCl{}+HNO3->HAuCl4{}+NO\uparrow +2H2O}}} Gold
26607-405: The recovery of gold from ore), can be highly toxic to people and wildlife even at relatively low concentrations. Illegal gold mining exacerbates the ecological vulnerability of the remaining forest ultimately leading to permanent forest loss. Gold mining clears native forests for mineral extraction, but also indirectly facilitates access to more land and further clearing. Rainforest recovery rates are
26788-416: The reign of Bogdan I around 1360. A local dynasty ruled the Despotate of Dobruja in the second half of the 14th century, but the Ottoman Empire took possession of the territory after 1388. Princes Mircea I and Vlad III of Wallachia , and Stephen III of Moldavia defended their countries' independence against the Ottomans. Most Wallachian and Moldavian princes paid
26969-403: The resignation of Romania's Prime Minister Victor Ponta. During 2017–2018, in response to measures which were perceived to weaken the fight against corruption, some of the biggest protests since 1989 took place in Romania, with over 500,000 people protesting across the country. Nevertheless, there have been significant reforms aimed at tackling corruption. A National Anticorruption Directorate
27150-401: The rest of the gold on Earth is thought to have been incorporated into the planet since its very beginning, as planetesimals formed the mantle . In 2017, an international group of scientists established that gold "came to the Earth's surface from the deepest regions of our planet", the mantle, as evidenced by their findings at Deseado Massif in the Argentinian Patagonia . On Earth, gold
27331-410: The rivers Dniester and Dnieper) under Romanian administration. Romanian and German troops massacred at least 160,000 local Jews in these territories; more than 105,000 Jews and about 11,000 Gypsies died during their deportation from Bessarabia to Transnistria. Most of the Jewish population of Moldavia, Wallachia, Banat and Southern Transylvania survived, but their fundamental rights were limited. After
27512-533: The same regions. The reliability of the Gesta is debated. Some scholars regard it as a basically accurate account, others describe it as a literary work filled with invented details. The Pechenegs seized the lowlands abandoned by the Hungarians to the east of the Carpathians. Byzantine missionaries proselytised in the lands east of the Tisa from the 940s and Byzantine troops occupied Dobruja in the 970s. The first king of Hungary , Stephen I , who supported Western European missionaries, defeated
27693-403: The same result and showing that the isotopes of gold produced by it were all radioactive . In 1980, Glenn Seaborg transmuted several thousand atoms of bismuth into gold at the Lawrence Berkeley Laboratory. Gold can be manufactured in a nuclear reactor, but doing so is highly impractical and would cost far more than the value of the gold that is produced. Although gold is the most noble of
27874-412: The separate status of Transylvania in the Habsburg Monarchy, but the Austro-Hungarian Compromise brought about the union of the province with Hungary in 1867. Ethnic Romanian politicians sharply opposed the Hungarian government's attempts to transform Hungary into a national state, especially the laws prescribing the obligatory teaching of Hungarian. Leaders of the Romanian National Party proposed
28055-486: 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 . These are called lode deposits. 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
28236-472: The sluice box. A rocker box uses less water than a sluice box and is well suited for areas where water is limited. A rocking motion provides the water movement needed for the gravity separation of gold in placer material. Rocker boxes gained popularity during the California Gold Rush in the 19th century and remain in use today. Although simple and inexpensive, it is not efficient as the previously discussed mining techniques . The dominant method for refining gold
28417-399: 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 610 BC. The legend of the golden fleece dating from eighth century BCE may refer to the use of fleeces to trap gold dust from placer deposits in the ancient world. From the 6th or 5th century BC,
28598-478: The steppes north of the Lower Danube in the 830s, but the Bulgarians and the Pechenegs jointly forced them to abandon this region for the lowlands along the Middle Danube around 894. Centuries later, the Gesta Hungarorum wrote of the invading Magyars' wars against three dukes— Glad , Menumorut and the Vlach Gelou —for Banat, Crișana and Transylvania. The Gesta also listed many peoples—Slavs, Bulgarians, Vlachs, Khazars , and Székelys —inhabiting
28779-407: The sultan's right to confirm the election of the princes. Mihail Kogălniceanu , Nicolae Bălcescu and other leaders of the 1848 revolutions in Moldavia and Wallachia demanded the emancipation of the peasants and the union of the two principalities, but Russian and Ottoman troops crushed their revolt. The Wallachian revolutionists were the first to adopt the blue, yellow and red tricolour as
28960-462: The surrounding rock or sediments. Unlike hard-rock mining, which involves excavating solid rock formations, water or dredging is used to extract the gold. Using a sluice box to extract gold from placer deposits has long been a very common practice in prospecting and small-scale mining. Sluices work on the principle that heavier particles will sink to the bottom of a stream, while those that are lighter will be carried downstream and expelled. A sluice box
29141-436: 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. In some cases, gold has a fractional oxidation state. A representative example is the octahedral species {Au( P(C 6 H 5 ) 3 )} 2+ 6 . Gold
29322-403: The transmutation of the chemical elements did not become possible until the understanding of nuclear physics in the 20th century. The first synthesis of gold was conducted by Japanese physicist Hantaro Nagaoka , who synthesized gold from mercury in 1924 by neutron bombardment. An American team, working without knowledge of Nagaoka's prior study, conducted the same experiment in 1941, achieving
29503-408: The union of Moldavia and Wallachia and gained independence from the Ottoman Empire in 1877. During World War I , Romania joined the Allies , and after the war, territories including Transylvania and Bukovina were integrated into Romania. In World War II , Romania initially aligned with the Axis but switched to the Allies in 1944. After the war, Romania became a socialist republic and
29684-495: The use of sluice boxes. Evidence suggests that Nubia had sporadic access to gold nuggets during the Neolithic and Prehistoric Period . Gold mining in Egypt involved both surface mining such as panning for gold in riverbeads and underground mining, where tunnels were dug to extract gold-bearing quartz veins. During the Bronze Age , sites in the Eastern Desert became a great source of gold-mining for nomadic Nubians, who used "two-hand-mallets" and "grinding ore extraction ." By
29865-399: The value of gold has led to millions of small, artisanal miners in many parts of the Global South . Like all mining, human rights and environmental issues are common in the gold mining industry, and can result in environmental conflict . In mines with less regulation, health and safety risks are much higher. The exact date that humans first began to mine gold is unknown, but some of
30046-592: The violent Romanian Revolution of December 1989 in which thousands were killed or injured. After a trial, Ceaușescu and his wife were executed by firing squad at a military base outside Bucharest on 25 December 1989. The charges for which they were executed were, among others, genocide by starvation. After the 1989 revolution, the National Salvation Front (FSN), led by Ion Iliescu , took partial and superficial multi-party democratic and free market measures after seizing power as an ad interim governing body. In March 1990, violent outbreaks went on in Târgu Mureș as
30227-417: The visors of heat-resistant suits and in sun visors for spacesuits . Gold is a good conductor of heat and electricity . Gold has a density of 19.3 g/cm , almost identical to that of tungsten at 19.25 g/cm ; as such, tungsten has been used in the counterfeiting of gold bars , such as by plating a tungsten bar with gold. By comparison, the density of lead is 11.34 g/cm , and that of
30408-459: The war against the Central Powers in 1916. The German and Austrian-Hungarian troops defeated the Romanian army and occupied three-quarters of the country by early 1917. After the October Revolution turned Russia from an ally into an enemy, Romania was forced to sign a harsh peace treaty with the Central Powers in May 1918, but the collapse of Russia also enabled the union of Bessarabia with Romania . King Ferdinand again mobilised
30589-441: The war, bringing about a rapprochement between Romania and the Triple Entente of France, Russia and the United Kingdom. The country remained neutral when World War I broke out in 1914, but Prime Minister Ion I. C. Brătianu started negotiations with the Entente Powers. After they promised Austrian-Hungarian territories with a majority of ethnic Romanian population to Romania in the Treaty of Bucharest , Romania entered
30770-474: The world's gold. Sometimes open-pit mining is used, such as at the Fort Knox Mine in central Alaska. Barrick Gold Corporation has one of the largest open-pit gold mines in North America located on its Goldstrike mine property in north eastern Nevada. Other gold mines use underground mining, where the ore is extracted through tunnels or shafts. South Africa has the world's deepest hard rock gold mine up to 3,900 metres (12,800 ft) underground. At such depths,
30951-611: The world, the Grasberg mine in Papua, Indonesia, is primarily a copper mine. Gold panning , or simply panning , is a form of placer mining and traditional mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts especially because of its low cost and relative simplicity. The first recorded instances of placer mining are from ancient Rome , where gold and other precious metals were extracted from streams and mountainsides using sluices and panning ( ruina montium ). Placer mining
31132-661: Was China with 368.3 tonnes of gold mined in that year. The second-largest producer of gold was Russia where 331.1 tonnes was mined in the same year, followed by Australia with 327.8 tonnes. In 2023, the annual gold demand of 4,448 tonnes was 5% below that of 2022. The total gold demand in 2023 was the highest at 4,899 tonnes. Despite its decreasing content in ores, gold production is increasing. This increase can be achieved through ever larger-scale industrial installations as well as innovations, especially in hydrometallurgy . Hard rock mining extracts gold encased in rock, rather than fragments in loose sediment, and produces most of
31313-736: Was abandoned for a fiat currency system after the Nixon shock measures of 1971. In 2020, the world's largest gold producer was China, followed by Russia and Australia. As of 2020 , a total of around 201,296 tonnes of gold exist above ground. This is equal to a cube, with each side measuring roughly 21.7 meters (71 ft). The world's consumption of new gold produced is about 50% in jewelry, 40% in investments , and 10% in industry . Gold's high malleability, ductility, resistance to corrosion and most other chemical reactions, as well as conductivity of electricity have led to its continued use in corrosion-resistant electrical connectors in all types of computerized devices (its chief industrial use). Gold
31494-432: Was again united under Decebalus around 85 AD. He resisted the Romans for decades, but the Roman army defeated his troops in 106 AD. Emperor Trajan transformed Banat , Oltenia , and the greater part of Transylvania into a new province called Roman Dacia , but Dacian and Sarmatian tribes continued to dominate the lands along the Roman frontiers. The Romans pursued an organised colonisation policy, and
31675-405: Was discovered in 1961. Official estimates indicate that total world gold production since the beginning of civilization has been around 6,352,216,000 troy ounces (197,576.0 t) and total gold production in Nevada is 1.1% of that, ranking Nevada as one of the Earth's primary gold-producing regions. World gold production was 3,612 tonnes in 2022. As of 2020, the world's largest gold producer
31856-450: Was elected president, in 2000 Iliescu returned to power, while Traian Băsescu was elected in 2004 and narrowly re-elected in 2009. In 2009, the country was bailed out by the International Monetary Fund as an aftershock of the Great Recession in Europe . In November 2014, Sibiu former FDGR/DFDR mayor Klaus Iohannis was elected president, unexpectedly defeating former Prime Minister Victor Ponta , who had been previously leading in
32037-463: Was formed in the country in 2002, inspired by similar institutions in Belgium , Norway and Spain . Since 2014, Romania launched an anti-corruption effort that led to the prosecution of medium- and high-level political, judicial and administrative offenses by the National Anticorruption Directorate . After the end of the Cold War , Romania developed closer ties with Western Europe and the United States, eventually joining NATO in 2004, and hosting
32218-409: Was one of the most long-lasting and strongest in the Eastern Bloc. A 2006 commission estimated the number of direct victims of the Communist repression at two million people. In 1965, Nicolae Ceaușescu came to power and started to conduct the country's foreign policy more independently from the Soviet Union. Thus, communist Romania was the only Warsaw Pact country which refused to participate in
32399-398: Was the first Dacian ruler to unite the local tribes. He also conquered the Greek colonies in Dobruja and the neighbouring peoples as far as the Middle Danube and the Balkan Mountains between around 55 and 44 BC. After Burebista was murdered in 44 BC, his kingdom collapsed. The Romans reached Dacia during Burebista's reign and conquered Dobruja in 46 AD. Dacia
32580-486: Was to distort 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 300 km (190 mi) diameter crater caused by the meteor strike. The discovery of the deposit in 1886 launched the Witwatersrand Gold Rush . Some 22% of all the gold that is ascertained to exist today on Earth has been extracted from these Witwatersrand rocks. Much of
32761-422: Was under the control of the state but the mines may have been leased to civilian contractors some time later. The gold served as the primary medium of exchange within the empire, and was an important motive in the Roman conquest of Britain by Claudius in the first century AD; although there is only one known Roman gold mine at Dolaucothi in west Wales. Gold was a prime motivation for the campaign in Dacia when
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