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Sterling silver is an alloy of silver containing 92.5% pure silver and 7.5% other metals, usually copper. The minimum millesimal fineness is 925.
Fine silver (99.9% pure) is generally too soft for producing large functional objects, and in Sterling the silver is usually alloyed with copper to give strength while preserving the ductility of the silver and a high precious metal content. Other metals can replace the copper, usually with the intent to improve various properties of the basic sterling alloy such as reducing casting porosity, eliminating firescale, and increasing resistance to tarnish. These replacement metals include germanium, zinc, platinum as well as a variety of other additives including silicon and boron. A number of alloys claiming firescale and/or tarnish resistance have appeared in recent years sparking heavy competition between the various manufacturers and their different formulations. No one alloy has emerged as an industry leader or standard and ongoing alloy development is a very active area.
Additional recommended knowledge
Origin of the term
The term "Sterling Silver," in reference to the .925 grade of silver, emerged in England by the 13th century.
The terms "sterling" and "pound sterling", seem to have acquired their meaning over a while, and from several convergent sources. The first mention is that of "sterilensis" in 1078, and by the thirteenth century (the 1200s) the term sterling had appeared. "Sterling" is believed to come from the Old Norman French esterlin (meaning little star) and Old English stiere (strong, firm, immovable).
Mint mark theory
The 1955 edition of the Oxford English Dictionary states that the early Middle English name sterling was presumably descriptive of small stars that were visible on early Norman pennies. (Old English: steorling.) Although marks of birds have been used in some coins of Edward the Confessor, sterling is not likely to have been derived from starling, as the word for starling at the time was spelt stær; if the coin had been named after the bird, it would have been shortened to starling.
An alternative explanation put forth by Walter de Pinchebek circa 1300 is that Sterling Silver may have been known first as "Easterling Silver". The term "Easterling Silver" is believed to have been used to refer to the grade of silver that had originally been used as the local currency in an area of Germany, known as "The Easterling".
This "Easterling" area consisted of five towns in the northern part of Germany (east of England) that banded together in the 12th century under the name Hanseatic League. The Hanseatic League proceeded to engage in considerable commerce with England. In payment for English cattle and grain, the League used their local currency. This currency was in the form of 92.5% silver coins. England soon learned that these coins, which they referred to as "the coins of the Easterlings", were of a reliably high quality and hardness.
King Henry II set about to adopt the alloy as the standard for English currency. He recruited metal refiners from The Easterling and put them to work making silver coins for England. The silver these refiners produced came into usage as currency by 1158 in the form of what are now known as "Tealby Pennies", and was eventually adopted as a standard alloy throughout England. The original name "Easterling Silver" was later abbreviated to "Sterling Silver".
The original English silver penny was 22½ troy grains of fine silver (as pure as can readily be made). 22½ troy grains is equivalent to 30 so called Tower grains or one Tower pennyweight. When Henry II reformed the coinage, he based the now coinage on the then international standard of the troy pound rather than the pre-conquest English standard of the Tower pound. A troy pennyweight is 24 troy grains. To maintain the same amount of silver (and thus the same value) in a coin that weighed more required less silver. It required that the alloy be only 92½% pure.
Though coin weights and silver purity varied considerably (reaching a low point before the reign of Elizabeth I, who reinstated Sterling Silver coinage for the first time since the early 14th century), the pound sterling was used as currency in England from the 12th century until the middle of the 20th century. Specifically this was in the silver coins of the British Empire: Britain, British colonies, and some former British colonies. This sterling coin silver is not to be confused with the Coin silver standard.
Sterling silver, no longer used in circulating currency, is still used for flatware, jewelery and plate, and is a grade of silver respected for both relatively high purity and sufficient hardness to form durable objects in daily use.
A sterling silver object that is to be sold commercially is, in many countries, taken to an assay office for testing of the purity of the metal. The item is then marked, usually via hammer and punch, with the hallmark of that particular nation. Because this process leaves sharp edges and spurs of metal, it is generally done before the item is sent for its final wheel polishing.
The hallmark for sterling silver varies from nation to nation. The United Kingdom and Ireland have a highly structured hallmarking system. The stamps on British and Irish sterling silver impart a wide range of information. First, a stamp to indicate the purity of the silver was applied. This was usually a Lion Passant, but there were variations over the years. Next was a letter to indicate the date. The typeface, whether the letter is uppercase or lowercase, and even the shape inside which the letter is stamped, must all be taken together to determine the year. Last to be stamped was a symbol to indicate the city in which the piece was manufactured. For example, a crown of a certain style indicated the city of Sheffield, while an anchor indicated the city of Birmingham (both well-known for silver production). This system of hallmarking is still in use today.
The French hallmark for sterling silver was the head of the goddess Minerva. In fact, the French standard for sterling silver was higher than that of other nations, requiring a silver content of 950 parts per thousand. Silver items with a slightly lower grade of silver, 800 parts per thousand, were also manufactured, and these were marked with the head of Minerva, next to which was a "2". (Pieces from other nations also were manufactured in this lower grade of silver, but are stamped "800".)
In some countries, such as the United States, no national hallmark was ever adopted, although the city of Baltimore did maintain its own assay office between 1814-1830. The words "STERLING", "925", or "coin" were simply stamped into the piece. Because of this, some companies within the U.S., such as Tiffany and Gorham, adopted their own marking systems. For example, pieces from the Gorham company can be identified by a Lion Passant (or Lion Rampant, depending on the year), an anchor and the letter "G", and sometimes an accompanying number to indicate the style.
In addition to the hallmarks, silver manufacturers often applied their own specific stamp. For example, the letters "T. and Co." indicates a piece manufactured by Tiffany and Company. As mentioned above, the letter "G" indicated the Gorham Company. These stamps were as unique as today's logos, and disputes often arose when one company copied another's stamp.
The difficulty with hallmarking systems other than those of the United Kingdom and Ireland are that in most cases one cannot pinpoint the manufacture to a specific year, but instead to a range of years during which the company was in business. Many larger companies did put out yearly catalogs, however, and these can be used as a reference to narrow down the date of a specific piece. In fact, there are people who make a good income doing research on the history of specific sterling pieces.
Due to sterling silver having a very special characteristic in sound resonance, some brasswind instrument manufacturers use 92.5% sterling silver as the material for making their instruments, including the flute and saxophones. For example, some leading saxophone manufactuers such as Selmer and Yanagisawa have crafted some of their saxophones from sterling silver, which they believe will make the instruments more resonant and colorful in timbre.
Other silver standards
Fine silver is 99.9% silver or better. This grade of silver is used to make bullion bars for international commodities trading. In the modern world Fine Silver is understood to be too soft for general use.
Britannia silver is purer than sterling, at least 95.84% silver and up to 4.16% copper. Its marks were Britannia and a lion's head in profile.
The Britannia standard was a standard of plate obligatory in Britain between 1697 and 1720 to try to help prevent British sterling silver coins from being melted to make plate. It became an optional standard thereafter, and in the United Kingdom and Ireland is now denoted by the millesimal fineness hallmark "958", with the symbol of Britannia being applied optionally.
Mexican silver is also purer than sterling, usually 95% Silver and 5% Copper. Mexico is the only country currently using silver in its circulating coinage, but these coins are not minted from 95% "Mexican" Silver. Much of the currently produced silver jewelry and other decorative silver objects made in Mexico at the present time are made according to the Sterling, i.e. 92.5% silver, standard, and are marked "Sterling".
Coin silver is most commonly 90% silver and 10% copper as dictated by United States FTC guidelines. "Coin Silver" is said to have acquired its name because much of it was made from melting down silver coins, which are generally of the 90% standard. This does allow for some variation in the silver content, depending on which coinage was used to create the silver stock.
Coin silver is usually lower in silver content than sterling. The Coin standard came into common use for table silver in the US during the 1820s, and lasted until 1868. This grade of silver was used in the silver coinage of the US, (until 1964) and also by other countries that minted silver currency , such as Panama and the Philippines.
German silver (not to be confused with nickel silver, which is also referred to by this same term) are several silver standards used in Germany. However, the most common standard for silverware and decorative silver objects is the 800 standard (80% pure silver). Hence, when the term German silver is used, it is usually referred to as the 800 standard. Another silver standard in use is the 900 standard. German silver objects are usually marked with an "800" or "900" to show the standard to which they are made. The UK Assay offices also recognise the 80% silver content which is legally represented by the 800 stamp.
For industrial uses, for example in electronics, alloys such as copper-silver, CuAg, are favored, which contains 72% silver and 28% copper and is known for its thermal conductivity.
History of sterling silver and dining regalia
From about 1840 to somewhere around 1940 in the United States and Europe, sterling silver flatware became de rigueur when setting a proper table. In fact, there was a marked increase in the number of silver companies that emerged during that period.
The height of the silver craze was during the 50-year period from 1870 to 1920. Flatware lines during this period sometimes included up to 100 different types of pieces. In conjunction with this, the dinner went from three courses to sometimes ten or more. There was a soup course, a salad course, a fruit course, a cheese course, an antipasto course, a fish course, the main course and a pastry or dessert course.
Individual eating implements often included forks (dinner fork, place fork, salad fork, pastry fork, shrimp or cocktail fork), spoons (teaspoon, coffee spoon, demitasse spoon, bouillon spoon, gumbo soup spoon, iced tea spoon) and knives (dinner knife, place knife, butter spreader, fruit knife, cheese knife). This was especially true during the Victorian time period, when etiquette dictated that nothing should be touched with one's fingers.
Serving pieces were often elaborately decorated and pierced and embellished with ivory, and could include any or all of the following: carving knife and fork, salad knife and fork, cold meat fork, punch ladle, soup ladle, gravy ladle, casserole serving spoon, berry spoon, lasagna server, macaroni server, asparagus server, cucumber server, tomato server, olive spoon, cheese scoop, fish knife and fork, pastry server, petit four server, cake knife, bon bon spoon, sugar sifter or caster and crumb remover with brush.
Flatware sets were often accompanied by tea services, hot water pots, chocolate pots, trays and salvers, goblets, demitasse cups and saucers, liqueur cups, bouillon cups, egg cups, sterling plates, napkin rings, water and wine pitchers and coasters, candelabra and even elaborate centerpieces.
In fact, the craze with sterling even extended to business (sterling page clips, mechanical pencils, letter openers, calling card boxes, cigarette cases), to the boudoir (sterling dresser trays, mirrors, hair and suit brushes, pill bottles, manicure sets, shoe horns, perfume bottles, powder bottles, hair clips) and even to children (cups, flatware, rattles, christening sets).
A number of factors converged to make sterling fall out of favor around the time of World War II. The cost of labor rose (sterling pieces were all still mostly man-made, with only the basics being done by machine). Only the wealthy could afford the large number of servants required for fancy dining with ten courses. And changes in aesthetics resulted in people desiring simpler dinnerware that was easier to clean. (The latter was especially important as more became known about disease.)
As the purity of the silver decreases, the problem of corrosion or tarnishing also increases.
Chemically, silver is not very reactive — it does not react with oxygen or water at ordinary temperatures, so does not easily form a silver oxide. However, the other metal in the alloy, usually copper, may react with oxygen in the air.
The black silver sulfide (Ag2S) is among the most insoluble salts in aqueous solution, a property that is exploited for separating silver ions from other positive ions.
Sodium Chloride (NaCl) or common table salt is known to corrode silver-copper alloy, typically seen in silver salt shakers where corrosion appears around the holes in the top.
Wikibooks' Do-It-Yourself has more about this subject:
Several products have been developed for the purpose of polishing silver that serve to remove sulphur from the metal without damaging or warping it. Because harsh polishing and buffing can permanently damage and devalue an antique piece of silver, valuable items are typically hand-polished to preserve the unique patinas of older pieces. Techniques such as wheel polishing, which are typically performed by professional jewelers or silver repair companies, are reserved for extreme tarnish or corrosion. An easy way to shine silver is to take some dry baking soda and rub it on the metal with one's fingers, then to rinse it with mineral-free water. See also Tarnish, Removal.
Categories: Silver | Alloys | Precious metal alloys
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sterling_silver". A list of authors is available in Wikipedia.|