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69-507: The name is a portmanteau of two words: "Subarna," meaning gold, and "Rekha," meaning line or streak in Indian languages. As per tradition, gold was mined near the origin of the river at a village named Piska near Ranchi , hence the name Subarnarekha or "streak of gold". Legend has it that traces of gold were found in the riverbed. Even now, people look for traces of gold particles in its sandy beds. After originating near Piska/Nagri, near Ranchi,

138-399: 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

207-434: 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

276-483: 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

345-572: 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

414-830: 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,

483-552: 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

552-462: 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

621-706: A result of unplanned mining activities, the river is polluted. The Subarnarekha has been the lifeline of tribal communities inhabiting the Chhotanagpur region and water pollution affects their livelihood. It is getting more pollutants from the aluminium factory of Muri. Several areas in the lower reaches of the Subarnarekha, particularly the coastal areas of Odisha and West Bengal, are within the flood hazard zone. The Subarnarekha in Odisha had crossed its previous Highest Flood Level (HFL) of 12.2 metres (40 ft) in 2007, surpassing

690-401: 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

759-423: 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

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828-517: 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,

897-470: 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,

966-696: 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

1035-469: 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

1104-648: 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

1173-520: 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

1242-427: 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

1311-513: 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

1380-464: 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

1449-465: 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

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1518-528: 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,

1587-450: Is one of the most visited places of Jharkhand. The museum located close to the Chandil dam has scripts written on rocks, which are 2,000 years old. The Government of Odisha has signed a memorandum of understanding with Chennai-based Creative Port Development Pvt. Ltd. for the development of a deep-water, all-weather project at Kirtania at the mouth of the Subarnarekha. The Kirtania Port project

1656-427: 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

1725-484: 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

1794-585: 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

1863-634: 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

1932-505: 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

2001-416: 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

2070-645: 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

2139-583: 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

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2208-809: The Sutlej River till its terminus near the Tibet border. NH5 traverses the states of Punjab , Haryana , Himachal Pradesh and union territory of Chandigarh in India. Firozpur , Moga , Jagraon, Ludhiana , Kharar, Morinda, Mohali - Chandigarh border Punjab border at Mohali, exits at Zirakpur in Punjab Zirakpur - Haryana border Punjab border - Panchkula , Surajpur, Pinjore , Kalka bypass - H.P. border Haryana border - Parwanoo , Solan , Shimla , Theog , Narkanda , Kumarsain , Rampur Bushahr , Chini, Shipki La at Sino-Indian border This section contains

2277-641: 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

2346-470: 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

2415-738: The Medinipur district of West Bengal through a left bank canal and its distribution system covering a culturable command area of 96,860 hectares (239,300 acres). The project was taken up for construction in the year 1995–96. The Chandil Dam and reservoir required 17,028 hectares (42,080 acres) of land. Icha Dam submerged 8,585 hectares (21,210 acres) of land in Jharkhand and 4,415 hectares (10,910 acres) of land in Orissa. The Ganjia Barrage required 266 hectares (660 acres) of land. Galudiha Barrage required 180 hectares (440 acres) of land, of which 150 hectares (370 acres)

2484-483: The Subarnarekha at Sonari (Domuhani), a neighborhood of Jamshedpur . Hundru Falls is created on the course of the Subarnarekha, where it falls from a height of 98 metres (322 ft). The spectacular sight of water falling from such a great height is a sight to behold. The different rock formations due to erosion by the constantly falling water have added to the beauty of the place. The Subarnarekha passes through areas with extensive mining of copper and uranium ores. As

2553-531: The Subernarekha, 40 kilometres (25 mi) east of Ranchi and about 50 kilometres (31 mi) from its point of origin. Completed in 1971, this multi-purpose reservoir was envisaged mainly to meet municipal water demands of Ranchi city and the adjoining industrial area. The height of the dam is 35.5 metres (116 ft). There are two power houses in Sikidiri with one unit of 65 MW each. Sikidiri Hydal Power Plants are

2622-529: The capital of Jharkhand, the Subarnarekha traverses a long distance through Ranchi , Seraikela Kharsawan, and East Singhbhum districts in the state. Thereafter, it flows for shorter distances through Paschim Medinipur district in West Bengal for 83 kilometres (52 mi) and Balasore district of Odisha. There, it flows for 79 kilometres (49 mi) and joins the Bay of Bengal near Talsari . The total length of

2691-1409: 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

2760-424: 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

2829-512: The earlier record of 1997. In 2009, the Subarnarekha witnessed flash floods following heavy rainfall in the upper catchment areas of the river. During the flood, large areas of Jaleswar, Bhograi and Baliapal blocks and a small pocket of Basta block in Balasore district of Odisha were affected. Certain areas of Medinipur in West Bengal are also affected by floods. Getalsud reservoir is located across

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2898-664: 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

2967-525: The first century AD. National Highway 5 (India) National Highway 5 ( NH5 ) is a primary national highway in India, running from West to East, connecting Firozpur in Punjab to the Sino - Indian border at Shipki La . The highway passes through Moga , Jagraon , Ludhiana , Mohali , Chandigarh , Panchkula , Kalka , Solan , Shimla , Theog , Narkanda , Kumarsain , Rampur Bushahr and continues along

3036-574: 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

3105-403: 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

3174-563: 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

3243-542: 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

3312-420: The multipurpose project was planned for irrigation, hydropower generation and water supply. While the Chandil dam and Galudih barrage are almost complete, the other components are still incomplete. Subernarekha Barrage project (West Bengal) envisages construction of a barrage across the Subarnarekha downstream of Chandil dam and Galudih barrage near Bhosraghat to irrigate 114,198 hectares (282,190 acres) annually in

3381-411: 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

3450-522: The only hydal projects in Jharkhand. The Subarnarekha multipurpose project envisaged the construction of two dams, one at Chandil across the Subarnarekha and the other across the Kharkai at Icha near Chaibasa , two barrages at Galudih across the Subarnarekha and the other across the Kharkai at Ganjia near Adityapur and a network of canals from these. Three small storage reservoirs and a network of canals from these reservoirs are in Orissa. Started in 1982–83,

3519-563: 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

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3588-459: 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

3657-681: 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

3726-620: 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

3795-420: 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

3864-935: 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

3933-464: 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

4002-419: The river is 395 kilometres (245 mi). The basin of the Subarnarekha is smaller than most multi-state river basins in India. The rain-fed river covers a drainage area of 18,951 square kilometres (7,317 sq mi) The prominent tributaries of the Subarnarekha are Kharkai , Roro, Kanchi, Harmu Nadi, Damra, Karru, Chinguru, Karakari, Gurma, Garra, Singaduba, Kodia, Dulunga and Khaijori. The Kharkai meets

4071-474: 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

4140-486: 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

4209-446: 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,

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4278-518: The spectre of the partition of Bengal in 1947. In the film Subarnarekha, Ghatak "has rendered the very idea of home as a sentimental place on an elusive other side that, like the distant, opposing banks of the Subarnarekha River, symbolically represents an idealized, and intranscendible, elsewhere." Gold Gold is a chemical element with the chemical symbol Au (from Latin aurum ) and atomic number 79. In its pure form, it

4347-436: 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

4416-403: 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

4485-417: 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

4554-783: 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

4623-470: Was being taken up on a 50-year build, own, operate, share and transfer (boost) basis. The development would include a dedicated rail cum road connection from the port to the NH 5 and rail network at Jaleswar . More recently the project is being referred to as Subarnarekha port. The foundation stone was laid in 2019. Ritwik Ghatak directed a Bengali film Subarnarekha in 1965. Ghatak's films are deeply haunted by

4692-488: Was private land and 30 hectares was Revenue Land. The canal network required additional land. The project experienced protests from its inception in 1975 and, in 1978, some 10,000 of them demonstrated against the dam at the construction site. To address the protests, the government increased the compensation package for 12,000 families and 2,200 people got jobs in different government departments. The construction of Chandil dam, Icha dam and Galudih barrage are complete. This dam

4761-605: 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

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