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Silver

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Silver is a chemical element with symbol Ag (Greek: άργυρος árguros, Latin: argentum, both from the Indo-European root *arg- for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it possesses the highest electrical conductivity of any element, the highest thermal conductivity of any metal and is the most reflective metal on the planet. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.

While silver has long been valued as a precious metal it is also used in currency coins, solar panels, water filtration, jewelry and ornaments, high-value tableware and utensils (hence the term silverware) and as an investment in the forms of coins and bullion. Silver is used industrially in electrical contacts and conductors, in specialized mirrors, window coatings and in catalysis of chemical reactions. Its compounds are used in photographic film and X-rays. Dilute silver nitrate solutions and other silver compounds are used as disinfectants and microbiocides (oligodynamic effect), added to bandages and wound-dressings, catheters and other medical instruments.

ilver is produced during certain types of supernova explosions by nucleosynthesis from lighter elements through the r-process, a form of nuclear fusion that produces many elements heavier than iron, of which silver is one.

Silver is a very ductile, malleable (slightly harder than gold), univalent coinage metal, with a brilliant white metallic luster that can take a high degree of polish. It is the most reflective metal on Earth.It has the highest electrical conductivity of all metals, even higher than copper, but its greater cost has prevented it from being widely used in place of copper for electrical purposes. An exception to this is in radio-frequency engineering, particularly at VHF and higher frequencies, where silver plating to improve electrical conductivity of parts, including wires, is widely employed. During World War II in the US, 13,540 tons were used in the electromagnets used for enriching uranium, mainly because of the wartime shortage of copper.

Among metals, pure silver has the highest thermal conductivity (the nonmetal carbon in the form of diamond and superfluid helium II are higher) and the highest optical reflectivity (protected silver has higher reflectance than aluminium at all wavelengths longer than ~450 nm; below 450 nm, silver is inferior to aluminium and its reflectance drops to zero near 310 nm).Silver is the best conductor of heat and electricity of any metal in the periodic table. Silver also has the lowest contact resistance of any metal. Silver halides are photosensitive and are remarkable for their ability to record a latent image that can later be developed chemically. Silver is stable in pure air and water, but tarnishes when it is exposed to air or water containing ozone or hydrogen sulfide, the latter forming a black layer of silver sulfide which can be cleaned off with dilute hydrochloric acid.The most common oxidation state of silver is +1 (for example, silver nitrate, AgNO3); the less common +2 compounds (for example, silver(II) fluoride, AgF2), and the even less common +3 (for example, potassium tetrafluoroargentate(III), KAgF4) and even +4 compounds (for example, potassium hexafluoroargentate(IV), K2AgF6) are also known.

Silver, in the form of electrum (a gold–silver alloy), was coined to produce money around 700 BC by the Lydians. Later, silver was refined and coined in its pure form. Many nations used silver as the basic unit of monetary value. In the modern world, silver bullion has the ISO currency code XAG. The name of the pound sterling (£) reflects the fact it originally represented the value of one pound Tower weight of sterling silver; other historical currencies, such as the French livre, have similar etymologies. During the 19th century, the bimetallism that prevailed in most countries was undermined by the discovery of large deposits of silver in the Americas; fearing a sharp decrease in the value of silver and thus the currency, most states switched to a gold standard by 1900. In some languages, such as Sanskrit, Spanish, French, and Hebrew, the same word means both silver and money.

The 20th century saw a gradual movement to fiat currency, with most of the world monetary system losing its link to precious metals after Richard Nixon took the United States dollar off the gold standard in 1971; the last currency backed by gold was the Swiss franc, which became a pure fiat currency on 1 May 2000. During this same period, silver gradually ceased to be used in circulating coins. In 1964, the United States stopped minting their silver dime and quarter. They minted their last circulating silver coin in 1970 in its 40% half-dollar.

In 1968, Canada minted their last circulating silver coins which were the 50% dime and the 50% quarter. The Royal Canadian Mint still makes many collectible silver coins with various dollar denominations. In addition to Canada, the United States and many other countries continue to mint silver coins that are collected for their bullion and numismatic value. The U.S. coin is known as the "Silver Eagle".

Silver is used as a currency by many individuals, and is legal tender in the US state of Utah.Silver coins and bullion are also used as an investment to guard against inflation and devaluation.

Jewelry and silverware

Jewelry and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. In the US, only an alloy consisting of at least 90.0% fine silver can be marketed as "silver" (thus frequently stamped 900). Sterling silver (stamped 925) is harder than pure silver, and has a lower melting point (893 °C) than either pure silver or pure copper.[9] 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 is formed, with improved properties, including resistance to firescale.

Sterling silver jewelry is often plated with a thin coat of .999 fine silver to give the item a shiny finish. This process is called "flashing". Silver jewelry can also be plated with rhodium (for a bright, shiny look) or gold (to produce silver gilt).

Silver is a constituent of almost all colored carat gold alloys and carat gold solders, giving the alloys paler color and greater hardness.[23] White 9 carat gold contains 62.5% silver and 37.5% gold, while 22 carat gold contains a minimum of 91.7% gold and 8.3% silver or copper or other metals.[23]

Historically, the training and guild organization of goldsmiths included silversmiths, as well, and the two crafts remain largely overlapping. Unlike blacksmiths, silversmiths do not shape the metal while it is red-hot, but instead, work it at room temperature with gentle and carefully placed hammer blows. The essence of silversmithing is to take a flat piece of metal and to transform it into a useful object using different hammers, stakes and other simple tools.

While silversmiths specialize in, and principally work silver, they also work with other metals, such as gold, copper, steel, and brass. They make jewelry, silverware, armor, vases, and other artistic items. Because silver is such a malleable metal, silversmiths have a large range of choices with how they prefer to work the metal. Historically, silversmiths are mostly referred to as goldsmiths, which was usually the same guild. In the western Canadian silversmith tradition, guilds do not exist; however, mentoring through colleagues becomes a method of professional learning within a community of craftspeople.

Traditionally, silversmiths mostly made "silverware" (cutlery, tableware, bowls, candlesticks and such). Only in more recent times has silversmithing become mainly work in jewelry, as much less solid silver tableware is now handmade.

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