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	SILVER - LoveToKnow Article on SILVER (Site not responding. Last check: 2007-10-20)
		This is illustrated by the hexagonal pyrargyrite 3Ag1S~SbzS1, and proustite, 3AgISAs2S1, and the monoclinic pyrostilpnite, isomeric with pyrargyrite, and xanthoconite, isomeric with proustite.
		The so-called oxidized silver is a copper-silver alloy coated superficially with a layer of the sulphides by immersion in sodium sulphide or otherwise.
		Silver fluoride, AgF, is obtained as quadratic octahedra, with one molecule of water, by dissolving the oxide or carbonate in hydrofluoric acid.
	32.1911encyclopedia.org /S/SI/SILVER.htm (6686 words)

	Encyclopedia: Silver
		Silver is a chemical element in the periodic table that has the symbol Ag (from the traditional abbreviation for the Latin Argentum, from which the Argentina is named) and atomic number 47.
		Silver is found in native form, combined with sulfur, arsenic, antimony, or chlorine and in various ores such as argentite (Ag) and horn silver (AgCl).
		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 membranes.
	www.nationmaster.com /encyclopedia/Silver (7552 words)

	Wolds Silver - Silver Matters
		OE seolfor; akin to OHG silbar silver, Lith sidabras] is a metallic element represented by the chemical symbol Ag, and is one of the so-called transition elements in group 11 (Ib) of the periodic table.
		Silver is one of the most malleable and ductile of all metals and is generally superior to most other metals with respect to its ability to conduct heat and electricity.
		Silver is usually recovered from silver ores by roasting the ore to convert the sulphides to sulphates, which are then precipitated.
	www.wolds-silver.freeuk.com /silver_properties_nojs.htm (791 words)

	Silver sulphide sol with ultrafine particle size - Patent 5167875
		A silver sulphide sol according to claim 4, wherein the grain growth restrainer is a water-soluble aliphatic or heterocyclic mercapto compound, the watersolubility of which is improved by a hydroxy or carboxy substituent.
		A silver sulphide sol according to claim 4, wherein the grain growth restrainer is an organic mercapto compound selected from the group consisting of a mercapto-pyrimidine, a 2-mercapto-benzthiazole, a 2-mercaptobenzimidazole, a 2-mercapto-thiazole, a 2-mercapto-benzoxazole, a 2-mercapto-1,2,4-triazole and a 1-phenyl-5-mercapto-tetrazole compound containing on the phenyl nucleus a substituent including a carboxy group to improve its watersolubility.
		By addition to a silver halide emulsion a rapid and easily reproducible sulphur sensitization is obtained which we may assume is due to the adsorption of the very small silver sulphide particles on the much larger silver halide grains having normally a grain size larger than 100 nm.
	www.freepatentsonline.com /5167875.html (4232 words)

	Method for processing a photographic silver halide emulsion material - Patent 4830949
		Silver halide emulsion materials with all their enormous advantages in sensitivity, spectral sensitisation and capability of producing fl-and-white and colour images with strong optical density and high resolving power have the drawback of requiring in conventional processing several processing liquids and a time consuming drying for the final image.
		Further, silver recovery from fixing liquids in large scale processing is nowadays a must for its economic importance and proceeds by the deposition of dissolved silver as metal or silver precipitate from the fixing liquid bulk.
		Silver chloride emulsions having a silver chloride coverage corresponding with an amount equivalent to 3 g of silver nitrate per m2 can according to the present invention be freed from silver chloride in less than 30 s by contact with said sheet or web at 50.degree.
	www.freepatentsonline.com /4830949.html (4992 words)

	Lalor, Cyclopaedia of Political Science, V.3, Entry 190, SILVER: Library of Economics and Liberty
		—Silver is found in its native state, and also occurs in combination with other substances in the form of ores and alloys, but is principally obtained from its sulphide, and from those ores of which it is a variable constituent, but existing in such large quantities as to be an object of metallurgical operations.
		—Silver is refined by the wet process by dissolving the bullion in acids, precipitating the silver by chlorine, and subsequently reducing it to a metallic state, or by precipitation with copper.
		Silver is also dissolved in solutions, or used in combination with acids, metals, or alkaline bases in chemical and medicinal preparations, and for manufacturing purposes, in a manner which prevents its recovery for further use.
	www.econlib.org /library/YPDBooks/Lalor/llCy960.html (4818 words)

	AMBIENT WATER QUALITY CRITERIA FOR SILVER
		Populations that are unusually susceptible to toxic effects from silver are those with dietary deficiencies of vitamin E or selenium, or those with genetically-based deficiencies in the metabolism of these essential nutrients.
		Theoretical calculations of organic and inorganic silver complexes indicate that, due to the low solubility of silver sulphide and the high affinity of silver for sulphide, little free silver would occur at equilibrium, in effluents or surface waters that contained any sulphide.
		Bioassays have demonstrated that, although 'free' silver caused the death of fathead minnows at relatively low silver concentrations, silver thiosulphate and silver sulphide salts had no effect at over 1000 times the `free' silver concentration.
	wlapwww.gov.bc.ca /wat/wq/BCguidelines/silver/bcsilver-02.htm (496 words)

	ERA Technology \| Impact of gaseous sulphides on electronic reliability - ERA Technology Ltd
		Hydrogen sulphide is well known as the classic "bad egg gas" of the school chemical laboratory, with its pungent, unpleasant and easily recognised smell, even at very low concentrations.
		Sulphide contact: Devices were used in steel plant, adjacent to blast furnaces that are certain to raise ambient levels of hydrogen sulphide, although no local measurements of its concentration were carried out.
		Sulphide contact: Contacts in an underground train system were not sealed against the environment and had operated for several years since the last service.
	www.era.co.uk /news/rfa_feature_03.asp (1338 words)

	reCollections: Caring for Cultural Material 2
		Silver's lustrous appearance and relatively low natural abundance, its corrosion resistance and ability to be easily worked have made it a prized metal.
		Silver plate or electroplate is formed when a thin layer of pure or sterling silver is deposited electrolytically on the surface of a base metal.
		If you must place a silver object in a display case which has previously been shown to be corrosive towards silver, add zinc oxide or an acid-free zinc carbonate blotter to the base of the case to absorb the damaging substances.
	www.amol.org.au /recollections/2/5/11.htm (1059 words)

	Police Coins - Silver
		Silver and gold are the oldest of coinage metals, with the earliest coins minted in electrum, a naturally occuring alloy of gold and silver.
		Silver is a somewhat rare and expensive coinage metal, although neither as rare nor expensive as gold.
		Silver is resistant to tarnishing in pure air and water, but exposure to ozone, sulphur, hydrogen sulphide and other compounds will cause tarnishing.
	www.policecoins.com /silver.html (415 words)

	AMBIENT WATER QUALITY CRITERIA FOR SILVER
		The toxicity of silver, as silver thiosulphate, to fathead minnow (Pimephales promelas) eggs and fry.
		The toxicity of silver, as silver sulphide, to fathead minnow (Pimephales promelas) eggs and fry.
		The distribution of ingested silver in the kidney of the rat and of the rabbit.
	wlapwww.gov.bc.ca /wat/wq/BCguidelines/silver/bcsilver-44.htm (2978 words)

	AMBIENT WATER QUALITY CRITERIA FOR SILVER
		Most toxicological studies have been conducted with silver in the free, elemental or 0 oxidation state, and with the +1 monovalent silver ion.
		Theoretical calculations of organic and inorganic silver complexes indicate that, due to the low solubility of silver sulphide and the high affinity of silver for sulphide, little free silver, usually <10 to 12 µg/L, would occur at equilibrium, in effluents or surface waters that contained any sulphide (IJC 1982).
		This is still the routine total or dissolved silver detection limit for water samples analyzed in labs used by the British Columbia Ministry of Environment for analysis of ambient water samples.
	wlapwww.gov.bc.ca /wat/wq/BCguidelines/silver/bcsilver-06.htm (514 words)

	Process for the production of silver powder from silver chloride, sulphate or sulphide - Patent 4388109
		A process according to claim 1 wherein the silver salt is silver chloride, and the silver chloride and sodium carbonate are mixed in the proportion of about 1 mole of sodium carbonate per mole of silver chloride.
		A process according to claim 1 wherein the silver salt is silver sulphate, and the silver sulphate and sodium carbonate are mixed in the proportions of about two moles of sodium carbonate per mole of silver sulphate.
		The silver chloride or sulphate and the sodium carbonate can be mixed in any manner which produced a thorough mixture, and the heating may be carried out in an ordinary atmosphere in a ceramic or suitable metallic reaction vessel.
	www.freepatentsonline.com /4388109.html (1483 words)

	Fading of Albumenized Prints, Elimination of Silver, etc.
		The existence of a compound of albumen and silver in the whites of the print, which is not removed by the fixing bath.
		The means of preventing the formation of sulphide of silver during fixing consist in thorough washing of the print before fixing, using the hypo solution fresh and strong, shielding it from the action of light and heat, and in the addition of an alkali, to which we shall presently advert.
		So long as this compound of silver with albumen, a substance containing sulphur, exists unremoved, it is liable to a decomposition, which will set up the fading action, which consists in the whites being degraded by turning yellow, and the fls losing force by turning yellow.
	albumen.stanford.edu /library/c19/pn-fade.html (1763 words)

	Silver - Applications and Properties of Silver
		Silver is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulphide, or air containing sulphur because of the formation of a silver sulphide.
		Silver powder that comes in several forms such as amorphous powder, dendritic crystals, atomised powder, silver-clad powder, silver flake and nickel-coated silver powder.
		Silver is of the upmost importance in photography (where approximately 30% of the U.S. Industrial consumption goes into this application).
	www.azom.com /Details.asp?ArticleID=600 (386 words)

	Silver_Introduction
		Silver occurs as metal and in silver ores such as Argentite (Ag S), often accompanied by copper, lead and zinc ores.
		Deposits of silver are also in Cobalt, Ontario and keremos and at several locations in the Yukon and the Northwest territories.
		Silver is not very resistant to contamination by sulphur as silver sulphide tarnishes silver.
	www.jewelleryytt.com /silver_introduction.htm (128 words)

	Method for the preparation of a planographic printing plate using NiS containing nuclei - Patent 4563410
		Therefor it is necessary to use a silver image receiving element wherein the major proportion of the development nuclei is concentrated atthe surface of the outer hydrophilic colloid layer rather than being distributed throughout the latter.
		The preparation of nickel sulphide and of mixed nickel sulphide-silver sulphide nuclei may proceed in aqueous medium by mixing a water-soluble nickel compound and optionally a water-soluble silver compound e.g.
		Onto the antihalation layer an orthochromatically sensitized silver chlorobromide emulsion (1.8% of bromide) was applied so that an amount of silver halide equivalent to 1.5 g of silver nitrate was present per sq.m with a gelatin to silver nitrate ratio of 1.
	www.freepatentsonline.com /4563410.html (4727 words)

	Remove Tarnish from Silver
		If the silver is badly tarnished, you may need to reheat the baking soda and water mixture, and give the silver several treatments to remove all of the tarnish.
		In the reaction, sulfur atoms are transferred from silver to aluminum, freeing the silver metal and forming aluminum sulfide.
		The silver and aluminum must be in contact with each other, because a small electric current flows between them during the reaction.
	scifun.chem.wisc.edu /HOMEEXPTS/TARNISH.html (626 words)

	On the Yellow Colouration of Faded Photographic Prints
		Sulphide of silver we know as a jet fl substance, and we habitually convert the reduced silver of negatives into sulphide when we wish to intensify them.
		Davanne and Girard answer as follows:--Sulphide of silver prepared by itself is, they say, fl; but, formed in presence of organic matter, the organic matter enters into the composition, and the compound is yellow.
		It appears that when the sulphide of silver is in a state of very fine division its colour is yellowish brown, as may be easily ascertained by treating a very dilute solution (e.g., 1-5,000th) of nitrate of silver with hydrosulphate of ammonia.
	albumen.stanford.edu /library/c19/lea3.html (688 words)

	Cultural Resource Survey for the Real de los Cerrillos Project - 03: Milford (Site not responding. Last check: 2007-10-20)
		The silver ores of Parral were formed in nearly vertical veins associated with Tertiary vulcanism (West, 1949, p.
		The supergene enrichment of sulphide ore by descending surface waters was one of the most significant factors affecting early colonial silver mining.
		This liberated the silver ions from the sulphur allowing the silver to go into solution and be carried downward in the vein by the surface water.
	www.cerrilloshills.org /mines/real03.htm (903 words)

	SCIENCE TRACK - Deccan Herald (Site not responding. Last check: 2007-10-20)
		When a thin coating of silver sulphide forms on the surface of silver, it darkens the metal.
		If you remove the silver sulphide by polishing the coin with a tarnish remover, some silver will naturally be rubbed off in the process.
		Another way to remove the silver sulphide is to reverse the tarnishing process, that is, by converting silver sulphide back to silver and sulphur.
	www.deccanherald.com /deccanherald/aug092004/snt2.asp (459 words)

	20432. What concentration of H2S is needed to tarnish silver? [UK]
		Silver will react with extremely low levels of hydrogen sulphide.
		You will be aware that silver will go fl in an atmosphere where you cannot smell hydrogen sulphide, so the minimum level will be in the ppb or even ppt range; however, the detection of the reaction will be dependent on how long the silver is exposed to the gas.
		Hydrogen sulphide and silver react to form fl silver sulphide, one of the most insoluble salts of silver and this is what causes the tarnish.
	www.finishing.com /204/32.shtml (333 words)

	Society of American Silversmiths - Argentium Sterling
		Sterling Silver, a registered and patented alloy developed by Peter Johns, is currently being produced by Stern Leach in the U.S. under a licensing agreement from Middlesex University, England.
		Sterling Silver to "rest" before quenching or forging since it tends to be a bit brittle at this temperature.
		Sterling Silver, depending on how the flame of the torch is used, some areas of the alloy may flen slightly on the first anneal.
	www.silversmithing.com /1argentium.htm (2149 words)

	Graham Noble and Diane Stirling, University of Glasgow: ABSORBENTS FOR THE PREVENTION OF SULPHIDATION OF SILVER
		Silver tarnishing is a problem experienced by all owners, curators and conservators of silver collections.
		The fl silver tarnish (silver sulphide) which forms as a result of the reaction of silver with sulphur-containing gases in the atmosphere detracts from the beauty of silver artefacts.
		In some cases, for example silver threads on historic textiles or daguerretype photographs, safe and effective tarnish removal is particularly difficult to accomplish.
	iaq.dk /iap/iap1999/1999_16.htm (595 words)

	Explanation of "Mustard Mystery" Experiment (Site not responding. Last check: 2007-10-20)
		If you eat eggs with a silver plated fork you will find that your fork has fl tarnish on it when you are finished.
		A silver crisis caused the replacement of silver in quarters and dimes in 1965.
		The half-dollar was composed of 40 percent silver from 1965 to 1970.
	www.sln.org /pieces/knox/mustardexplan.htm (214 words)

	After Treatment (Site not responding. Last check: 2007-10-20)
		The brown was originally achieved by bleaching out the silver mage with a solution similar - but not the same - to 'Farmers Reducer', then redeveloping in Sodium Sulphite which produced Silver Sulphide - brown crystals.
		As Silver Sulphide is a decay product and thus stable, pictures were relatively permanent.
		Thus, sepia toning of prints, the conversion of the silver to silver sulphide, was performed for the practical purpose of making prints permanent.
	www.freenetpages.co.uk /hp/paulbroad/15after.htm (2364 words)

	Mining Technology - Boliden Lead Mine - Laisvall - Sweden (Site not responding. Last check: 2007-10-20)
		Mineralisation was hosted in Eocambrian sandstones, with lead distribution seemingly affected by the presence of ridges of Precambrian basement rock and by local overthrusting in the sediments.
		Galena, sphalerite and pyrite were the principal sulphides, with native silver sometimes visible in association with galena.
		The relatively simple sulphide ores allowed Boliden to optimise the concentrator for lead recovery, at the same time achieving excellent silver and good zinc recoveries.
	www.mining-technology.com /projects/laisvall/index.html (691 words)

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