(from Wikipedia)<\/p>\n
Silver<\/strong>\u00a0is a\u00a0chemical element<\/a>\u00a0with the\u00a0symbol<\/a>\u00a0Ag<\/strong>\u00a0(from the\u00a0Latin<\/a>\u00a0argentum<\/em>, derived from the\u00a0Proto-Indo-European<\/a>\u00a0h<\/em>\u2082<\/em>er\u01f5<\/em><\/a>: “shiny” or “white”) and\u00a0atomic number<\/a>\u00a047. A soft, white, lustrous\u00a0transition metal<\/a>, it exhibits the highest\u00a0electrical conductivity<\/a>,\u00a0thermal conductivity<\/a>, and\u00a0reflectivity<\/a>\u00a0of any\u00a0metal<\/a>. The metal is found in the Earth’s crust in the pure, free elemental form (“native silver”), as an\u00a0alloy<\/a>\u00a0with\u00a0gold<\/a>\u00a0and other metals, and in minerals such as\u00a0argentite<\/a>\u00a0and\u00a0chlorargyrite<\/a>. Most silver is produced as a byproduct of\u00a0copper<\/a>, gold,\u00a0lead<\/a>, and\u00a0zinc<\/a>\u00a0refining<\/a>.<\/p>\n Silver has long been valued as a\u00a0precious metal<\/a>. Silver metal is used in many\u00a0bullion coins<\/a>, sometimes\u00a0alongside gold<\/a>: while it is more abundant than gold, it is much less abundant as a\u00a0native metal<\/a>.[5]<\/a><\/sup>\u00a0Its purity is typically measured on a\u00a0per-mille<\/a>\u00a0basis; a 94%-pure alloy is described as “0.940 fine”. As one of the seven\u00a0metals of antiquity<\/a>, silver has had an enduring role in most human cultures.<\/p>\n Other than in\u00a0currency<\/a>\u00a0and as an\u00a0investment<\/a>\u00a0medium (coins<\/a>\u00a0and\u00a0bullion<\/a>), silver is used in\u00a0solar panels<\/a>,\u00a0water filtration<\/a>,\u00a0jewellery<\/a>, ornaments, high-value tableware and utensils (hence the term\u00a0silverware<\/a>), in\u00a0electrical contacts<\/a>\u00a0and\u00a0conductors<\/a>, in specialized mirrors, window coatings, in\u00a0catalysis<\/a>\u00a0of chemical reactions, as a colorant in\u00a0stained glass<\/a>\u00a0and in specialised confectionery. Its compounds are used in\u00a0photographic<\/a>\u00a0and\u00a0X-ray<\/a>\u00a0film. Dilute solutions of\u00a0silver nitrate<\/a>\u00a0and other silver compounds are used as\u00a0disinfectants<\/a>\u00a0and microbiocides (oligodynamic effect<\/a>), added to\u00a0bandages<\/a>\u00a0and wound-dressings,\u00a0catheters<\/a>, and other\u00a0medical instruments<\/a>.<\/p>\n History<\/strong><\/p>\n Silver was one of the seven\u00a0metals of antiquity<\/a><\/u> that were known to prehistoric humans and whose discovery is thus lost to history.\u00a0In particular, the three metals of group 11, copper, silver, and gold, occur in the\u00a0elemental form<\/a><\/u>\u00a0in nature and were probably used as the first primitive forms of\u00a0money<\/a><\/u> as opposed to simple bartering.\u00a0However, unlike copper, silver did not lead to the growth of\u00a0metallurgy<\/a><\/u> on account of its low structural strength, and was more often used ornamentally or as money.\u00a0Since silver is more reactive than gold, supplies of native silver were much more limited than those of gold.[53]<\/a><\/sup><\/u> For example, silver was more expensive than gold in Egypt until around the fifteenth century BC:\u00a0the Egyptians are thought to have separated gold from silver by heating the metals with salt, and then reducing the\u00a0silver chloride<\/a><\/u>\u00a0produced to the metal.<\/u><\/p>\n The situation changed with the discovery of\u00a0cupellation<\/a><\/u>, a technique that allowed silver metal to be extracted from its ores. While\u00a0slag<\/a><\/u>\u00a0heaps found in\u00a0Asia Minor<\/a><\/u>\u00a0and on the islands of the\u00a0Aegean Sea<\/a><\/u>\u00a0indicate that silver was being separated from\u00a0lead<\/a>as early as the\u00a04th millennium BC<\/a><\/u>,\u00a0and one of the earliest silver extraction centres in Europe was\u00a0Sardinia<\/a><\/u>\u00a0in the early\u00a0Chalcolithic period<\/a><\/u>, these techniques did not spread widely until later, when it spread throughout the region and beyond. The origins of silver production in\u00a0India<\/a><\/u>,\u00a0China<\/a><\/u>, and\u00a0Japan<\/a><\/u>\u00a0were almost certainly equally ancient, but are not well-documented due to their great age.<\/u><\/p>\n When the\u00a0Phoenicians<\/a><\/u>\u00a0first came to what is now\u00a0Spain<\/a><\/u>, they obtained so much silver that they could not fit it all on their ships, and as a result used silver to weight their anchors instead of lead.[55]<\/a><\/sup><\/u>\u00a0By the time of the Greek and Roman civilizations, silver coins were a staple of the economy:<\/u>\u00a0the Greeks were already extracting silver from\u00a0galena<\/a><\/u>\u00a0by the 7th century BC,[55]<\/a><\/sup><\/u>\u00a0and the rise of\u00a0Athens<\/a><\/u>\u00a0was partly made possible by the nearby silver mines at\u00a0Laurium<\/a>, from which they extracted about 30 tones a year from 600 to 300 BC.<\/u>\u00a0The stability of the\u00a0Roman currency<\/a><\/u>\u00a0relied to a high degree on the supply of silver bullion, mostly from Spain, which\u00a0Roman miners<\/a> <\/u>produced on a scale unparalleled before the\u00a0discovery of the New World<\/a><\/u>. Reaching a peak production of 200 tones per year, an estimated silver stock of 10000 tones circulated in the\u00a0Roman economy<\/a><\/u>\u00a0in the middle of the second century AD, five to ten times larger than the combined amount of silver available to\u00a0medieval Europe<\/a><\/u>\u00a0and the\u00a0Abbasid Caliphate<\/a><\/u> around AD 800.\u00a0The Romans also recorded the extraction of silver in central and northern Europe in the same time period. This production came to a nearly complete halt with the fall of the Roman Empire, not to resume until the time of\u00a0Charlemagne<\/a><\/u>: by then, tens of thousands of tones of silver had already been extracted.<\/u><\/p>\n Central Europe became the centre of silver production during the\u00a0Middle Ages<\/a><\/u>, as the Mediterranean deposits exploited by the ancient civilisations had been exhausted. Silver mines were opened in\u00a0Bohemia<\/a><\/u>,\u00a0Saxony<\/a><\/u>,\u00a0Erzgebirge<\/a><\/u>,\u00a0Alsace<\/a><\/u>, the\u00a0Lahn<\/a><\/u>\u00a0region,\u00a0Siegerland<\/a><\/u>,\u00a0Silesia<\/a><\/u>,\u00a0Hungary<\/a><\/u>,\u00a0Norway<\/a><\/u>,\u00a0Steiermark<\/a><\/u>,\u00a0Salzburg<\/a><\/u>, and the southern\u00a0Black Forest<\/a><\/u>. Most of these ores were quite rich in silver and could simply be separated by hand from the remaining rock and then smelted; some deposits of native silver were also encountered. Many of these mines were soon exhausted, but a few of them remained active until the\u00a0Industrial Revolution<\/a><\/u>, before which the world production of silver was around a meagre 50 tones per year. In the Americas, high temperature silver-lead\u00a0cupellation<\/a><\/u> technology was developed by pre-Inca civilizations as early as AD 60\u2013120; silver deposits in India, China, Japan, and pre-Columbian America continued to be mined during this time.<\/u><\/p>\n With the discovery of America and the plundering of silver by the Spanish conquistadors, Central and South America became the dominant producers of silver until around the beginning of the 18th century, particularly\u00a0Peru<\/a><\/u>,\u00a0Bolivia<\/a><\/u>,\u00a0Chile<\/a><\/u>, and\u00a0Argentina<\/a>. <\/u><\/u>\u00a0the last of these countries later took its name from that of the metal that composed so much of its mineral wealth.[58]<\/a><\/sup><\/u> The silver trade this was a part of gave way to a global network of exchange. As one historian put it, silver “went round the world and made the world go round.” Much of this silver ended up in the hands of the Chinese.<\/p>\n In the 19th century, primary production of silver moved to North America, \u00a0\u00a0particularly \u00a0Canada<\/a><\/u>, \u00a0Mexico<\/a><\/u>, and\u00a0Nevada<\/a><\/u>\u00a0in the\u00a0United States<\/a><\/u>: some secondary production from lead and zinc ores also took place in Europe, and deposits in\u00a0Siberia<\/a><\/u>\u00a0and the\u00a0Russian Far East<\/a><\/u>\u00a0as well as in\u00a0Australia<\/a><\/u>\u00a0were mined.[56]<\/a><\/sup><\/u>\u00a0Poland<\/a><\/u> emerged as an important producer during the 1970s after the discovery of copper deposits that were rich in silver, before the centre of production returned to the Americas the following decade. Today, Peru and Mexico are still among the primary silver producers, but the distribution of silver production around the world is quite balanced and about one-fifth of the silver supply comes from recycling instead of new production.<\/u><\/p>\n Jewellery and silverware<\/strong><\/p>\n The major use of silver besides coinage throughout most of history was in the manufacture of\u00a0jewellery<\/a>\u00a0and other general-use items, and this continues to be a major use today. Examples include\u00a0table silver<\/a><\/u>\u00a0for cutlery, for which silver is highly suited due to its antibacterial properties.\u00a0Western concert flutes<\/a><\/u>\u00a0are usually plated with or made out of\u00a0sterling silver<\/a><\/u>;[93]<\/a><\/sup><\/u>\u00a0in fact, most silverware is only silver-plated rather than made out of pure silver; the silver is normally put in place by\u00a0electroplating<\/a><\/u>. Silver-plated glass (as opposed to metal) is used for mirrors,\u00a0vacuum flasks<\/a><\/u>, and Christmas tree decorations.<\/u><\/p>\n Because pure silver is very soft, most silver used for these purposes is alloyed with copper, with finenesses of 925\/1000, 835\/1000, and 800\/1000 being common. One drawback is the easy tarnishing of silver in the presence of\u00a0hydrogen sulfide<\/a><\/u>\u00a0and its derivatives. Including precious metals such as palladium, platinum, and gold gives resistance to tarnishing but is quite costly;\u00a0base metals<\/a><\/u>\u00a0like\u00a0zinc<\/a><\/u>,\u00a0cadmium<\/a><\/u>,\u00a0silicon<\/a><\/u>, and\u00a0germanium<\/a><\/u> do not totally prevent corrosion and tend to affect the lustre and colour of the alloy. Electrolytically refined pure silver plating is effective at increasing resistance to tarnishing. The usual solutions for restoring the lustre of tarnished silver are dipping baths that reduce the silver sulfide surface to metallic silver, and cleaning off the layer of tarnish with a paste; the latter approach also has the welcome side effect of polishing the silver concurrently. A simple chemical approach to removal of the sulfide tarnish is to bring silver items into contact with aluminium foil whilst immersed in water containing a conducting salt, such as sodium chloride.<\/p>\n","protected":false},"excerpt":{"rendered":" (from Wikipedia) Silver\u00a0is a\u00a0chemical element\u00a0with the\u00a0symbol\u00a0Ag\u00a0(from the\u00a0Latin\u00a0argentum, derived from the\u00a0Proto-Indo-European\u00a0h\u2082er\u01f5: “shiny” or “white”) and\u00a0atomic number\u00a047. A soft, white, lustrous\u00a0transition metal, it exhibits the highest\u00a0electrical conductivity,\u00a0thermal conductivity, and\u00a0reflectivity\u00a0of any\u00a0metal. The metal is found in the Earth’s crust in the pure, free elemental form (“native silver”), as an\u00a0alloy\u00a0with\u00a0gold\u00a0and other metals, and in minerals such as\u00a0argentite\u00a0and\u00a0chlorargyrite. Most silver is produced as a byproduct of\u00a0copper, gold,\u00a0lead, and\u00a0zinc\u00a0refining. Silver has long been valued as a\u00a0precious metal. Silver metal is used in many\u00a0bullion coins, sometimes\u00a0alongside gold: while it is more abundant than gold, it is much…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/pages\/1913"}],"collection":[{"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/comments?post=1913"}],"version-history":[{"count":11,"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/pages\/1913\/revisions"}],"predecessor-version":[{"id":2245,"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/pages\/1913\/revisions\/2245"}],"wp:attachment":[{"href":"https:\/\/oferantichitati.ro\/silverantiques\/wp-json\/wp\/v2\/media?parent=1913"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}