View source for Silver

{{Elementbox_header | number=47 | symbol=Ag | name=silver | left=[[palladium]] | right=[[cadmium]] | above=[[copper|Cu]] | below=[[gold|Au]] | color1=#ffc0c0 | color2=black }}
{{Elementbox_series | [[transition metal]]s }}
{{Elementbox_groupperiodblock | group=11 | period=5 | block=d }}
{{Elementbox_appearance_img | Ag,47| lustrous white metal }}
{{Elementbox_atomicmass_gpm | 107.8682[[List of elements by atomic mass|(2)]] }}
{{Elementbox_econfig | &#91;[[krypton|Kr]]&#93; 4d<sup>10</sup> 5s<sup>1</sup> }}
{{Elementbox_epershell | 2, 8, 18, 18, 1 }}
{{Elementbox_section_physicalprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_color | [[silver (color)|silver]] }}
{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 10.49 }}
{{Elementbox_densityliq_gpcm3mp | 9.320 }}
{{Elementbox_meltingpoint | k=1234.93 | c=961.78 | f=1763.2 }}
{{Elementbox_boilingpoint | k=2435 | c=2162 | f=3924 }}
{{Elementbox_heatfusion_kjpmol | 11.28 }}
{{Elementbox_heatvaporiz_kjpmol | 250.58 }}
{{Elementbox_heatcapacity_jpmolkat25 | 25.350 }}
{{Elementbox_vaporpressure_katpa | 1283 | 1413 | 1575 | 1782 | 2055 | 2433 | comment=}}
{{Elementbox_section_atomicprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_crystalstruct | face-centered cubic }}
{{Elementbox_oxistates | 1<br />([[amphoteric]] oxide) }}
{{Elementbox_electroneg_pauling | 1.93 }}
{{Elementbox_ionizationenergies3 | 731.0 | 2070 | 3361 }}
{{Elementbox_atomicradius_pm | 160 }}
{{Elementbox_atomicradiuscalc_pm | 165 }}
{{Elementbox_covalentradius_pm | 153 }}
{{Elementbox_vanderwaalsrad_pm | 172 }}
{{Elementbox_section_miscellaneous | color1=#ffc0c0 | color2=black }}
{{Elementbox_magnetic | [[diamagnetism|diamagnetic]] }}
{{Elementbox_eresist_ohmmat20 | 15.87 n}}
{{Elementbox_thermalcond_wpmkat300k | 429 }}
{{Elementbox_thermaldiff_wpmkat300k | 174 }}
{{Elementbox_thermalexpansion_umpmkat25 | 18.9 }}
{{Elementbox_speedofsound_rodmpsatrt | 2680 }}
{{Elementbox_youngsmodulus_gpa | 83 }}
{{Elementbox_shearmodulus_gpa | 30 }}
{{Elementbox_bulkmodulus_gpa | 100 }}
{{Elementbox_poissonratio | 0.37 }}
{{Elementbox_mohshardness | 2.5 }}
{{Elementbox_vickershardness_mpa | 251 }}
{{Elementbox_brinellhardness_mpa | 24.5 }}
{{Elementbox_cas_number | 7440-22-4 }}
{{Elementbox_isotopes_begin | color1=#ffc0c0 | color2=black }}
{{Elementbox_isotopes_decay2 | mn=105 | sym=Ag
 | na=[[synthetic radioisotope|syn]] | hl=41.2 d
 | dm1=[[electron capture|ε]] | de1=- | pn1=105 | ps1=[[palladium|Pd]]
 | dm2=[[gamma ray|γ]] | de2=0.344, 0.280,<br /> 0.644, 0.443 | pn2=| ps2=- }}
{{Elementbox_isotopes_decay2 | mn=106[[nuclear isomer|m]] | sym=Ag
 | na=[[synthetic radioisotope|syn]] | hl=8.28 d
 | dm1=[[electron capture|ε]] | de1=- | pn1=106 | ps1=[[palladium|Pd]]
 | dm2=[[gamma ray|γ]] | de2=0.511, 0.717,<br /> 1.045, 0.450 | pn2=| ps2=- }}
{{Elementbox_isotopes_stable | mn=107 | sym=Ag | na=51.839% | n=60 }}
{{Elementbox_isotopes_decay3 | mn=108[[nuclear isomer|m]] | sym=Ag
 | na=[[synthetic radioisotope|syn]] | hl=418 y
 | dm1=[[electron capture|ε]] | de1=- | pn1=108 | ps1=[[palladium|Pd]]
 | dm2=[[isomeric transition|IT]] | de2=0.109 | pn2=108 | ps2=Ag 
 | dm3=[[gamma ray|γ]] | de3=0.433, 0.614,<br /> 0.722 | pn3=| ps3=-}}
{{Elementbox_isotopes_stable | mn=109 | sym=Ag | na=48.161% | n=62 }}
{{Elementbox_isotopes_decay2 | mn=111 | sym=Ag
 | na=[[synthetic radioisotope|syn]] | hl=7.45 d
 | dm1=[[beta decay|β<sup>-</sup>]] | de1=1.036, 0.694 | pn1=111 | ps1=[[cadmium|Cd]]
 | dm2=[[gamma ray|γ]] | de2=0.342 | pn2=| ps2=- }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffc0c0 | color2=black }}


== Overview ==
'''Silver''' ({{pronEng|ˈsɪlvɚ}}) is a [[chemical element]] with the symbol "Ag" ({{lang-la|argentum}}) and atomic number 47. A soft, white, lustrous [[transition metal]], it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. It occurs as a free metal (native silver) as well as in various [[mineral]]s, such as [[argentite]] and [[chlorargyrite]]. Most silver is produced as a by-product of [[copper]], [[gold]], [[lead]], and [[zinc]] mining.

Silver has been known since antiquity, and it is used as a currency metal. It has long been valued as a [[precious metal]] used in ornaments and jewellery and in high-value tableware and utensils (hence the term "[[silverware]]"). Today, it is used in [[photographic film]], electrical contacts and conductors, and mirrors. Elemental silver is also used to [[Catalysis|catalyze]] chemical reactions. Silver is antimicrobial, and dilute solutions of [[silver nitrate]] and other silver compounds are used as [[disinfectant]]s. Although silver has largely been supplanted by other treatments, the [[antiseptic]] properties of silver are still a useful tool in the prevention and treatment of [[sepsis]] and [[infection]]s caused by [[antibiotic]]-[[antibiotic resistance|resistant]] [[microorganisms]] such as [[Methicillin-resistant Staphylococcus aureus|MRSA]]. 

== Occurrence and extraction == 
{{Main|Silver mining}}

[[Image:Silver - world production trend.svg|thumb|left|Time trend of silver production]]
Silver is found in native form; combined with [[sulfur]], [[arsenic]], [[antimony]], or [[chlorine]]; and in various ores, such as [[argentite]] (Ag<sub>2</sub>S), [[horn silver]] (AgCl), and [[pyrargyrite]] (Ag<sub>3</sub>SbS<sub>3</sub>). The principal sources of silver are the ores of copper, copper-nickel, gold, lead, and lead-zinc obtained from [[Peru]], [[Mexico]], [[China]], and [[Australia]]. Peru and Mexico have been mining silver since 1546 and are still major world producers. 

The metal can also be produced during the [[electrolysis|electrolytic]] refining of copper and by application of the [[Parkes process]] on lead metal obtained from lead ores that contain small amounts of silver. Commercial-grade fine silver is at least 99.9% pure silver, and purities greater than 99.999% are available. In 2005, [[Peru]] was the top producer of silver with almost one-seventh world share, closely followed by Mexico, according to the [[British Geological Survey]].

== Notable characteristics == 
[[Image:SilverUSGOV.jpg|thumb|left|A nugget of silver]]

Silver is a very [[Ductility|ductile]] and [[Malleability|malleable]] (slightly harder than [[gold]]) monovalent [[coinage metal]] with a brilliant white metallic luster that can take a high degree of [[polishing|polish]]. It has the highest [[electrical conductivity]] of all [[metals]], even higher than copper, but its greater cost and [[tarnish]]ability have prevented it from being widely used in place of copper for electrical purposes, though it was used in the [[electromagnets]] used for enriching [[uranium]] during [[World War II]] (mainly because of the wartime shortage of copper). Another notable exception is in [[high-end audio cables]], although the actual benefits of its use in this application are questionable.

Among metals, pure silver has the highest [[thermal conductivity]] (only the non-metal [[diamond]]'s is higher), whitest color, the highest optical [[reflectivity]] (although [[aluminium]] slightly outdoes it in parts of the visible spectrum, and it is a poor reflector of [[ultraviolet]] light). Silver also has the lowest [[contact resistance]] of any metal. [[Silver halide]]s are [[Photosensitive#Interpretation in chemistry|photosensitive]] and are remarkable for their ability to record a [[latent image]] that can later be [[photographic developer|develop]]ed chemically. Silver is stable in pure air and water, but [[tarnish]]es when it is exposed to air or water containing [[ozone]] or [[hydrogen sulfide]]. The most common [[oxidation state]] of silver is +1 (for example, [[silver nitrate]]: AgNO<sub>3</sub>); a few +2 (for example, [[silver(II) fluoride]]: AgF<sub>2</sub>) and +3 compounds (for example, potassium tetrafluoroargentate: K[AgF<sub>4</sub>]) are also known.

== Isotopes == 
{{main|isotopes of silver}}
Naturally occurring silver is composed of the two stable [[isotope]]s, <sup>107</sup>Ag and <sup>109</sup>Ag, with <sup>107</sup>Ag being the more abundant (51.839% [[natural abundance]]). Silver's standard atomic mass is 107.8682(2) u. 
Twenty-eight [[radioisotope]]s have been characterised, the most stable being <sup>105</sup>Ag with a [[half-life]] of 41.29 days, <sup>111</sup>Ag with a half-life of 7.45 days, and <sup>112</sup>Ag with a half-life of 3.13 hours.

All of the remaining [[radioactive]] isotopes have half-lives that are less than an hour, and the majority of these have half-lives that are less than 3 minutes. This element has numerous [[meta state]]s, the most stable being <sup>108m</sup>Ag (''t''<sub>* </sub> 418 years), <sup>110m</sup>Ag (''t''<sub>* </sub> 249.79 days) and <sup>106m</sup>Ag (''t''<sub>* </sub> 8.28 days).

Isotopes of silver range in [[atomic weight]] from 93.943 [[atomic mass unit|u]] (<sup>94</sup>Ag) to 123.929 u (<sup>124</sup>Ag). The primary [[decay mode]] before the most abundant stable isotope, <sup>107</sup>Ag, is [[electron capture]] and the primary mode after is [[beta decay]]. The primary [[decay product]]s before <sup>107</sup>Ag are [[palladium]] (element 46) isotopes, and the primary products after are [[cadmium]] (element 48) isotopes.

The palladium [[isotope]] <sup>107</sup>Pd decays by beta emission to <sup>107</sup>Ag with a half-life of 6.5 million years. [[Iron]] [[meteorite]]s are the only objects with a high-enough palladium-to-silver ratio to yield measurable variations in <sup>107</sup>Ag abundance. [[Radiogenic]] <sup>107</sup>Ag was first discovered in the [[Santa Clara, California|Santa Clara]] meteorite in 1978. The discoverers suggest that the coalescence and differentiation of iron-cored small [[planet]]s may have occurred 10 million years after a [[nucleosynthetic]] event. <sup>107</sup>Pd–<sup>107</sup>Ag correlations observed in bodies that have clearly been melted since the [[accretion (science)|accretion]] of the [[solar system]] must reflect the presence of live short-lived nuclides in the early solar system.

== Silver compounds ==
* [[Silver carbonate]] is used to remove [[carbon dioxide]] from the air.
* [[Silver chloride]] can be made transparent and is used as a [[cement]] for glass.
* [[Silver chloride]] is a widely used electrode for [[pH]] testing and [[potentiometric]] measurement.
* [[Silver fulminate]] is a powerful [[explosive]].
* [[Silver iodide]] has been used in attempts to [[Cloud seeding|seed clouds]] to produce rain.
* [[Silver nitrate]] is used as an [[antiseptic]] and in some chemical reactions.
* [[Silver sulfide]], also known as [[silver whiskers]], is formed when silver [[electrical contact]]s are used in an atmosphere rich in [[hydrogen sulfide]].
* [[Silver oxide]] is used as a positive electrode ([[cathode]]) in watch batteries.

== Applications == 
[[Image:Gilt silver eared cup.jpg|thumb|right|240px|A [[China|Chinese]] [[Tang Dynasty]] ([[618]]–[[907]] CE) [[gilding|gilt]]-silver cup with flower design]]
=== As a precious metal ===
A major use of silver is as a [[precious metal]] and it has long been used for making high-value objects reflecting the wealth and status of the owner. Jewellery and silverware are traditionally made from [[sterling silver]] (standard silver), an alloy of 92.5% silver with 7.5% copper. Sterling silver is harder than pure silver and has a lower melting point (893 °C) than either pure silver or pure copper. [[Britannia silver]] is an alternative hallmark-quality standard containing 95.8% silver, often used to make silver tableware and wrought plate. With the addition of [[germanium]], the patented modified alloy [[Argentium sterling silver|Argentium Sterling Silver]] is formed, with improved properties including resistance to [[firescale]].

Silver is used in medals, denoting second place. Some high-end [[musical instruments]] are made from sterling silver, such as the [[flute]]. 

=== In dentistry ===
The malleability and non-toxicity of silver make it useful in [[amalgam]]s for dental fittings and fillings. 

=== In photography and electronics ===
Photography used 24% of the silver consumed in 2001 in the form of [[silver nitrate]] and silver [[halogen|halides]], while 33% was used in jewellery, 40% for industrial uses, and only 3% for coins and medals.<ref>Butterman, WC & Hilliard, HE (2005) Silver. Open file report 2004-1251. US Geological Survey mineral commodity profiles, Reston, Virginia. </ref>

Some electrical and electronic products use silver for its superior conductivity, even when tarnished. For example, [[Printed circuit board|printed circuits]] are made using silver paints,<ref name=lanl>[[Los Alamos National Laboratory]], [http://periodic.lanl.gov/elements/47.html Silver], accessed 12 Feb 2007.</ref> and computer keyboards use silver electrical contacts. Some high-end audio hardware ([[Digital-to-analog converter|DAC]]s, [[preamplifier]]s, etc.) are fully silver-wired, which is believed to cause the least loss of quality in the signal. Silver cadmium oxide is used in high voltage contacts because it can withstand [[electric arc|arcing]]. 

[[Image:Silver (mined)2.PNG|thumb|Silver output in 2005]]
[[Image:SilverOreUSGOV.jpg|thumb|left|Silver ore (Lincoln cent is shown for scale)]]
[[Image:03414 silver Cobalt-Ontario.jpg|thumb|left|Silver leaf on andesine rock]]

=== In solder and brazing ===
Silver is also used to make [[solder]] and [[brazing]] alloys, [[electrical contact]]s, and high-capacity [[Silver-oxide battery|silver-zinc]] and [[Silver-cadmium battery|silver-cadmium]] [[Battery (electricity)|batteries]]. Silver in a thin layer on top of a bearing material can provide a significant increase in galling resistance and reduce wear under heavy load, particularly against steel.

=== In mirrors and optics ===
[[Mirror]]s which need superior reflectivity for visible light are made with silver as the reflecting material in a process called [[silvering]], though common mirrors are backed with aluminium. Using a process called [[sputtering]], silver (and sometimes gold) can be applied to glass at various thicknesses, allowing different amounts of light to penetrate. This is most often seen in architectural glass and tinted windows on vehicles.

=== As a catalyst ===
Silver's catalytic properties make it ideal for use as a [[catalyst]] in oxidation reactions, for example, the production of [[formaldehyde]] from [[methanol]] and air by means of silver screens or [[crystallite]]s containing a minimum 99.95&nbsp;weight-percent silver. Silver (upon some suitable support) is probably the only catalyst available today to convert [[ethylene]] to [[ethylene oxide]] (later hydrolyzed to [[ethylene glycol]], used for making [[polyester]]s)—a very important industrial reaction.

[[Oxygen]] dissolves in silver relatively easily compared to other gases present in air. Attempts have been made to construct silver [[artificial membrane|membrane]]s of only a few [[monolayer]]s thickness. Such a membrane could be used to filter pure oxygen from air.

=== As money ===
Silver, in the form of [[electrum]], was coined to produce money in around 700 BCE by the [[Lydia]]ns. Later, silver was refined and coined in its pure form (''see [[silver coin]]''). Many nations used silver as the basic unit of monetary value (''see [[Silver standard]]'').  The words for "silver" and "money" are the same in at least 14 languages. In the modern world, silver [[bullion]] has the [[ISO 4217|ISO currency code]] XAG. 

The name of the United Kingdom monetary unit "pound" reflects the fact that it originally represented the value of one [[troy pound]] of sterling silver. 

In the 1800s, many nations, such as the [[United States]] and [[Great Britain]], switched from silver to a [[gold standard]] of monetary value, then in the 20th century to [[fiat currency]].

=== In medicine === 
Silver ions and silver compounds show a toxic effect on some bacteria, viruses, algae and fungi, typical for heavy metals like [[lead (element)|lead]] or [[mercury (element)|mercury]], but without the high toxicity to humans that is normally associated with them. Its germicidal effects kill many microbial organisms ''[[in vitro]]''. 

[[Hippocrates]], the father of modern medicine, wrote that silver had beneficial healing and anti-disease properties, and the [[Phoenicians]] used to store water, [[wine]], and [[vinegar]] in silver bottles to prevent spoiling. In the early 1900s people would put [[silver dollar]]s in milk bottles to prolong the milk's freshness. Its germicidal effects increase its value in utensils and as jewellery. The exact process of silver's germicidal effect is still not well understood, although theories exist. One of these is the [[oligodynamic effect]], which explains the effect on microbial lifeforms but does not explain certain antiviral effects.

Silver compounds were used successfully to prevent infection in [[World War I]] before the advent of [[antibiotic]]s. Silver nitrate solution was a standard of care but was largely replaced by [[silver sulfadiazine]] cream (SSD Cream)<ref>Te-Wen Chang and Louis Weinstein, "Prevention of Herpes Keratoconjunctivitis in Rabbits By Silver Sulfadiazine" Antimicrob Agents Chemother. 1975 December; 8(6): 677–678. PMID 429446</ref> which was generally the "standard of care" for the antibacterial and antibiotic treatment of serious burns until the late 1990s. Now, other options, such as silver-coated dressings (activated silver dressings), are used in addition to SSD cream and may present advantages such as pain reduction and capacity for treatment at home. 

The widespread use of silver went out of fashion with the development of modern antibiotics. However, recently there has been renewed interest in silver as a broad-spectrum antimicrobial. In particular, it is being used with [[alginate]], a naturally occurring [[biopolymer]] derived from seaweed, in a range of [[silver alginate]] products designed to prevent infections as part of [[wound]] management procedures, particularly applicable to [[Burn (injury)|burn]] victims. In 2007, [[Asahi Glass Co.|AGC Flat Glass Europe]] introduced the first antibacterial glass to fight hospital-caught infection: it is covered with a thin layer of silver.<ref>{{cite web | title= AGC Flat Glass Europe launches world’s first antibacterial glass | url = http://www.agc-flatglass.eu/AGC+Flat+Glass+Europe/English/Homepage/News/Press+room/Press-Detail-Page/page.aspx/979?pressitemid=1031 | date = 2007-09-04 }}</ref>  In addition, [[Samsung]] has introduced [[washing machine]]s with a final rinse containing silver ions to provide several days of antibacterial protection in the clothes.<ref>{{cite web | title=Samsung laundry featuring SilverCare Technology | publisher=Samsung | url=http://web.archive.org/web/20060531115914/http://www.samsung.com/PressCenter/PressRelease/PressRelease.asp?seq=20060213_0000233684 | accessdate=2007-08-06 }}</ref> [[Kohler Company|Kohler]] has introduced a line of toilet seats that have silver ions embedded to kill germs. A company called Thomson Research Associates has begun treating products with Ultra Fresh, an anti-microbial technology involving "proprietary nano-technology to produce the ultra-fine silver particles essential to ease of application and long-term protection."<ref>{{cite web | title="Ultra-Fresh technology is based on the power of silver to fight bacteria" | publisher=Express Textile | url=http://www.expresstextile.com/20050731/perspectives01.shtml }}</ref> The [[FDA]] has recently approved an [[endotracheal tube|endotracheal breathing tube]] with a fine coat of silver for use in [[mechanical ventilation]], after studies found it reduced the risk of ventilator-associated [[pneumonia]].<ref name="FDA Silver">{{cite web | url= http://www.fda.gov/bbs/topics/NEWS/2007/NEW01741.html| title= FDA Clears Silver-Coated Breathing Tube For Marketing| author= | date= 2007-11-08| publisher= | accessdate=2007-11-11 }}</ref>

==== As a medication ====
Today, various kinds of silver compounds, or devices to make solutions or [[colloids]] containing silver, are sold as remedies for a wide variety of diseases. Although most are harmless, some people using these home-made solutions excessively have developed [[argyria]] over a period of months or years. Several cases have been documented in medical literature, including one case of coma associated with high intake of silver. It is strongly advised to consult a doctor before embarking on such treatment.

Silver is widely used in topical gels and impregnated into bandages  because of its wide-spectrum antimicrobial activity. The anti-microbial properties of silver stem from the chemical properties of its ionized form, Ag+. This ion forms strong molecular bonds with other substances used by bacteria to [[respire]], such as molecules containing [[sulfur]], [[nitrogen]], and [[oxygen]].<ref> Slawson, R. Van Dyke, M. Lee, H. Trevors "Germanium and Silver Resistance, Accumulation and Toxicity in Microorganisms" Plasmid 27, 72-79 (1992)</ref> Once the Ag+ ion complexes with these molecules, they are rendered unusable by the bacteria, depriving it of necessary compounds and eventually leading to the bacteria's death.

=== In food === 
In [[India]], foods, especially  sweets, can be found decorated with a thin layer of silver known as [[vark]]. Silver as a food additive is given the [[E number]] [[E174]] and is classed as a [[food coloring]]. It is used solely for external decoration, such as on [[chocolate]] confectionery, in the covering of [[dragées]] and the decoration of sugar-coated flour confectionery. In [[Australia]], it is banned as a food additive.

=== In clothing === 
[[Image:Athena-Schale Hildesheimer Silberfund.jpg|thumb|right|240px|Goddess [[Minerva]] on a [[Roman Republic|Roman]] silver plate, 1st century BCE]]
Silver inhibits the growth of [[bacteria]] and [[fungus|fungi]]. It keeps [[odour]] to a minimum and reduces the risk of bacterial and fungal [[infection]]. In clothing, the combination of silver and moisture movement (wicking) is the best combination to reduce the harmful effects of prolonged use in active and humid conditions.

Silver is used in clothing in two main forms:
* A form in which silver [[ion]]s are integrated into the [[polymer]] from which yarns are made (a form of [[nanotechnology]]) 
* A form in which the silver is physically coated onto the yarns. 
In both cases the silver prevents the growth of a broad spectrum of bacteria and fungi. At the same time, silver is a very skin-friendly and highly compatible agent to which – unlike many [[antibiotic]]s – bacteria rarely build up resistance.

Recorded use of silver to prevent infection dates to [[ancient Greece]] and [[Ancient Rome|Rome]]. It was rediscovered in the [[Middle Ages]], where it was used for several purposes, such as to disinfect water and food during storage, and also for the treatment of burns and wounds as wound dressing. In the 19th century, sailors on long ocean voyages would put silver [[coin]]s in barrels of water and [[wine]] to keep the liquid pure. Pioneers in America used the same idea as they made their journey from coast to coast.
Silver solutions were approved in the 1920s by the [[US Food and Drug Administration]] for use as antibacterial agents. Today, wound dressings containing silver are well established for clinical wound care and have recently been introduced in consumer products such as sticking plasters.{{Fact|date=May 2007}}

== History == 
The word "silver" appears in [[Old English language|Anglo-Saxon]] in various spellings such as ''seolfor'' and ''siolfor''. A similar form is seen throughout the Teutonic languages (compare [[Old High German]] ''silabar'' and ''silbir''). 
The symbol "Ag" is from the Latin for "silver", ''argentum'' (compare Greek αργυρος (argyros)), from the Indo-European root ''arg-'' meaning "white" or "shining".

Silver has been known since ancient times. It is mentioned in the [[book of Genesis]], and slag heaps found in [[Asia Minor]] and on the islands of the [[Aegean Sea]] indicate that silver was being separated from [[lead]] as early as the [[4th millennium]] [[BCE]].

== Price ==
{{main|Silver as an investment|Silver standard}}

Silver is currently about 1/50th the price of [[gold]] by mass and approximately 70 times more valuable than [[copper]]. Silver once traded at 1/6th to 1/12th the price of gold, prior to the [[Age of Discovery]] and the discovery of great silver deposits in the Americas, most notably the vast [[Comstock Lode]] in [[Virginia City]], [[Nevada]], USA. This then resulted in the debate over cheap [[Free Silver]] to benefit the agricultural sector, which was among the most prolonged and difficult in that country's history and dominated public discourse during the latter decades of the nineteenth century.

Over the last 100 years the price of silver and the gold/silver price ratio have fluctuated greatly due to competing industrial and [[Store of value|store-of-value]] demands. In 1980 the silver price rose to an all-time high of US$49.45 per [[troy ounce]]. By December 2001 the price had dropped to US$4.15 per ounce, and in May 2006 it had risen back as high as US$15.21 per ounce. [[As of 2006]], silver prices (and most other metal prices) have been rather volatile, for example, quickly dropping from the May high of US$15.21 per ounce to a June low of US$9.60 per ounce before rising back above US$12.00 per ounce by August.<ref>{{cite web | url=http://charts3.barchart.com/chart.asp?sym=SIY0&data=A&jav=adv&vol=Y&evnt=adv&grid=Y&code=BSTK&org=stk&fix=|publisher=Barchart.com | title=Silver Cash daily plot}}</ref>

It is of note that in [[Judaic Law]] the price of silver is important. The lowest [[fiscal]] amount that a Jewish court, or [[Beth Din]], can convene to adjudicate a case over is a ''shova pruta'' (value of a Babylonian ''prutra'' coin). This is fixed at 1/8 of a gram of pure, unrefined silver, at market price.

== Folklore and popular culture == 
Because of the mysticism surrounding silver's [[lunar]] associations, as well as the aesthetic qualities of the white, reflective metal that cause it to be associated with purity, silver in [[European folklore]] has long been traditionally believed to be an antidote to various maladies and mythical [[monsters]]. Notably, silver was believed to be a repellent against [[vampire]]s (this primarily originates from its holy connotations; also, mirrors were originally polished silver, and as such, vampires allegedly cannot be seen in them because they have no soul) and it was also believed that a [[werewolf]], in his bestial form, could only be killed by a weapon or bullet made of silver. This has given rise to the term "[[silver bullet]]", which is used to describe things that very effectively deal with one specific problem.

In the [[Gospels]], Jesus' disciple [[Judas Iscariot]] is infamous for having taken a bribe of silver from religious leaders in [[Jerusalem]] to turn [[Jesus Christ]] over to the Romans.

In [[heraldry]], the [[tincture (heraldry)|tincture argent]], in addition to being shown as silver (this has been shown at times with real silver in official representations), can also be shown as white. Occasionally, the word "silver" is used rather than argent; sometimes this is done across-the-board, sometimes to avoid repetition of the word "argent" in blazon.

== Precautions ==
Silver plays no known natural biological role in humans, and possible health effects of silver are a subject of dispute. Silver itself is not toxic but most [[:category:silver compounds|silver salts]] are, and some may be [[carcinogenic]].

Silver and compounds containing silver (like [[colloidal silver]]) can be absorbed into the [[circulatory system]] and become deposited in various body tissues leading to a condition called [[argyria]] which results in a blue-grayish pigmentation of the skin, eyes, and [[mucous membrane]]s. Although this condition does not harm a person's health, it is disfiguring and usually permanent. Argyria is rare, and mild forms are sometimes mistaken for [[cyanosis]].

== See also == 
{{Spoken Wikipedia|Silver.ogg|2005-09-01}}
{{Commonscat|Silver}}
{{wiktionary|silver}}
* [[Precious metal]]
* [[Silver as an investment]]
* [[Silver coin]]
* [[Silver standard]]
* [[Silver mining]]
* [[:category:Silver compounds|Silver compounds]]

== External links == 
* [http://www.webelements.com/webelements/elements/text/Ag/index.html WebElements.com &ndash; Silver]
* [http://minerals.usgs.gov/minerals/pubs/commodity/silver/ Silver Statistics and Information], [[United States Geological Survey|USGS]] publications on the worldwide production of silver 
* [http://www.silverinstitute.org The Silver Institute] A silver industry website
* [http://www.theodoregray.com/PeriodicTable/Elements/047/index.html A collection of silver items] Samples of silver
* [http://www.nymex.com/sil_pre_agree.aspx Current silver price and trading information]
* [http://digital.library.wisc.edu/1711.dl/EcoNatRes.Argentum Transport, Fate and Effects of Silver in the Environment]''

==References==
{{reflist|2}}

{{Jewellery Materials}}

[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Precious metals]]
[[Category:Silver| ]]
[[Category:Noble metals]]
[[Category:Electrical conductors]]

[[af:Silwer]]
[[am:ብር (Ag)]]
[[ar:فضة]]
[[ast:Plata]]
[[az:Gümüş]]
[[bn:রূপা]]
[[zh-min-nan:Ag (goân-sò͘)]]
[[be:Серабро]]
[[bs:Srebro]]
[[bg:Сребро]]
[[ca:Plata]]
[[cv:Кĕмĕл]]
[[ceb:Silver]]
[[cs:Stříbro]]
[[co:Argentu]]
[[za:Ngaenz]]
[[cy:Arian (elfen)]]
[[da:Sølv]]
[[de:Silber]]
[[et:Hõbe]]
[[el:Άργυρος]]
[[es:Plata]]
[[eo:Arĝento]]
[[eu:Zilar]]
[[fa:نقره]]
[[fr:Argent]]
[[fur:Arint]]
[[ga:Airgead (dúil)]]
[[gd:Airgead (meatailt)]]
[[gl:Prata (elemento)]]
[[gu:ચાંદી]]
[[ko:은]]
[[hy:Արծաթ]]
[[hi:रूप्यम्]]
[[hr:Srebro]]
[[io:Arjento]]
[[bpy:প্রাটা]]
[[id:Perak]]
[[is:Silfur]]
[[it:Argento]]
[[he:כסף (יסוד)]]
[[pam:Pilak]]
[[ka:ვერცხლი]]
[[sw:Agenti (fedha)]]
[[ht:Ajan]]
[[ku:Zîv]]
[[la:Argentum]]
[[lv:Sudrabs]]
[[lb:Sëlwer]]
[[lt:Sidabras]]
[[li:Zèlver]]
[[jbo:rijno]]
[[hu:Ezüst]]
[[ml:വെള്ളി]]
[[mi:Kawata]]
[[mr:चांदी]]
[[ms:Perak]]
[[nah:Iztac teōcuitlatl]]
[[nl:Zilver]]
[[ja:銀]]
[[no:Sølv]]
[[nn:Sølv]]
[[oc:Argent (metal)]]
[[uz:Kumush]]
[[nds:Sülver]]
[[pl:Srebro]]
[[pt:Prata]]
[[ksh:Silber]]
[[ro:Argint]]
[[qu:Qullqi q'illay]]
[[ru:Серебро]]
[[sq:Argjendi]]
[[scn:Argentu]]
[[simple:Silver]]
[[sk:Striebro]]
[[sl:Srebro]]
[[sr:Сребро]]
[[sh:Srebro]]
[[fi:Hopea]]
[[sv:Silver]]
[[ta:வெள்ளி (உலோகம்)]]
[[tt:Kömeş]]
[[te:వెండి]]
[[th:เงิน (ธาตุ)]]
[[vi:Bạc]]
[[tg:Нуқра]]
[[tr:Gümüş]]
[[uk:Срібло]]
[[ur:چاندی]]
[[vec:Arxento]]
[[yi:זילבער]]
[[zh-yue:銀]]
[[zh:銀]]


{{WH}}
{{WS}}
{{jb1}}