Silver
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Contributors: Tessa De Alarcon, Victoria Kitirattragarn
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Copyright: 2011. The Objects Group Wiki pages are a publication of the Objects Specialty Group of the American Institute for Conservation of Historic and Artistic Works. The Objects Group Wiki pages are published for the members of the Objects Specialty Group. Publication does not endorse or recommend any treatments, methods, or techniques described herein.
Begin with a brief summary or introduction (1-3 sentences) to your material of object type (most likely the title of your page, for example glass, ivory, basketry ). Don't forget to add images as appropriate!
Materials and technology[edit | edit source]
This section should be used to provide a basic synopsis or refresher of the topic being discussed. Many materials and object types already have excellent references in the form of journal articles, books, websites, Wikipedia entries, and more. Rather than repeat all of that information here, this is a good place to reference significant publications or resources in summary and refer readers directly to the original sources.
History[edit | edit source]
Silver is a naturally occurring transition metal found in combination with sulfides of lead, copper, and zinc but is more often extracted as a by-product from processing other ores and other metals. Due to its many desirable qualities (color, malleability, ductility, resistance to atmospheric oxidation, etc.), silver has been used to manufacture coins, ornaments, cutlery and jewelry throughout history. Additionally, it also has or had uses in electrical engineering, dentistry, photovoltaic cells and the photographic industry. Historically, a major use of silver has been in the form of silver bullion or coins (Encyclopedia Britannica 2025).
Silver mining started around 3000 B.C, evident from slag heaps found near ancient mines in Turkey and Greece (Periodic Table). Silversmiths began to produce objects with silver and traded it throughout Asia Minor and North Africa as early as 700 B.C. The Laurium mines, located near Athens, Greece, was the primary source of silver for over a thousand years (The Natural Sapphire Company).
German Silver: Otherwise known as Nickel Silver, German Silver is a copper alloy with nickel and zinc that has a ‘silver’ appearance. Originally used in China, German Silver was introduced to the western world in the 19th century by German metalworkers.
Materials[edit | edit source]
Silver (Ag) is a soft, lustrous, whitish/gray transition metal. It exhibits the highest known electrical and thermal conductivity of all metals and the least chemically reactive of the transition elements (Encyclopedia Britannica 2025). World production of silver is about 20,000 tonnes a year (Periodic Table).
Raw materials; composition; definitions; parts; types; substrate(s); surface decoration; finish; chemical, optical, physical, or thermal properties; etc. *Remember:
Technology[edit | edit source]
Pure silver is very soft and is often alloyed with other metals such as copper or zinc to increase the hardness. In the United States and England, sterling silver (925 silver) contains 92.5% silver and 7.5% copper and/or other metals. In continental Europe, products made of 80% silver are marked “800”. Silver marks, marker’s marks and hallmarks are marks stamped in the silver material and are useful references for makers, dates, alloys, and locations of production. A good online encyclopedia of makers’ marks can be found at: https://www.925-1000.com/index.html
Sources, processing, tools, fabrication, manufacture, design, construction, decorative techniques, etc.
Identification[edit | edit source]
In archaeological contexts the identification of metals is often general without additional analytical analysis to confirm the metal and its alloying components. The appearance of archaeological silver alloys is variable depending on the alloying elements, and the burial environment. This can make identification on visual examination alone unreliable. For example, silver objects often include some copper and depending on the amount of copper and the chemistry of the burial environment, the copper may corrode preferentially giving the object the appearance of a copper alloy rather than a silver object. Elemental analysis is a more reliable form of identification.
Portable X-ray fluorescence (pXRF) is often used to identify metals and the alloying components but is limited as a surface analysis technique, though it can be used on a cut surface in tandem with other analytical techniques. Typically, pXRF is used for semi-quantitative results unless standards of none compositions, are used to calibrate the results. If a sample is taken for metallographic analysis, the exposed surface can also be used for analysis with a variety of elemental analysis techniques including, XRF and SEM-EDS. ICP-MS (Inductively coupled plasma mass spectrometry), which requires a sample is removed, is also a method that has been used to identify metals and their components.
Manufacturing techniques can be identified using a variety of techniques. For non-invasive analysis, X-radiography is often used to determine if an object is worked or cast as these produce different textures on the X-ray. Working marks such as hammering produces variations in thickness that are often more clearly visible on an X-ray than through visual examination, while a cast object will have a more even and uniform appearance with a slight grain from the casting porosity. An invasive technique that is also commonly used is metallographic analysis. In this case a sample is removed and polished for examination. The sample is also often etched to reveal the metal grain structure which will indicate whether the object has been cast or worked. Cast objects typically have a dendritic structure, while worked and annealed objects have a granular structure. Repeated working and annealing will also affect the grain size (Scott 1992).
Deterioration[edit | edit source]
Silver tarnishes, appearing darker and dull, as sulfur compounds in the air react with the surface, forming silver sulfide (Periodic Table). The rate of tarnishing depends on a variety of environmental factors such as temperature, relative humidity, concentration of sulfur present, and the metal alloy itself. Often, the development of tarnishing is uneven, producing areas that are duller, darker, and/or of different colors (brown, orange, black etc). However, tarnished silver may be considered desirable as it creates visual contrast. Despite the visual change, tarnished silver does not lose structural stability (Encyclopedia Britannica 2025).
Material/object specific issues attributed to physical, chemical, or biological factors including light, heat, moisture, pollution, mechanical damage, faults in the design, poor quality materials, inherent vice, etc.
Conservation and care[edit | edit source]
This information is intended to be used by conservators, museum professionals, and members of the public for educational purposes only. It is not designed to substitute for the consultation of a trained conservator.
- To find a conservator, please visit AIC's Find a Conservator page.
- To learn how you can care for your personal heritage, please visit AIC's Resource Center.
Documentation[edit | edit source]
If appropriate: for examination or documentation issues specific to a material or object type, including tips for accurately and meaningfully documenting specific materials, common types of previous repairs or restoration, etc. For general recommendations, please refer to the Objects wiki article on Conservation Practices or for general conservation work practices, please refer to the main AIC wiki section on Work Practices.
Preventive conservation[edit | edit source]
Dry storage is best for metal alloy objects. One method for addressing active corrosion for metal objects is storage in microclimates, either using a sealable plastic container, or sealing the object in an Escal bag. By using a microclimate, chemical reactions such as corrosion and in particular active corrosion, can be slowed or stopped by removing either oxygen, moisture, or both from the environment. Silica gel is often used create dry microenvironments (Anderson and Riccardelli 2009). The revolutionary preservation system also uses an oxygen scavenger in addition to silica gel (Paterakis and Hickey-Friedman 2011).
Interventive treatments[edit | edit source]
Treatment of archaeological silver alloy objects has varied overtime, particularly in the ways the objects have been cleaned.
Mechanical Cleaning:
This is currently the preferred method for terrestrial sites and involves the use of scalpels and skewers while the object is cleaned under magnification. This method requires practice and skill and is time consuming.
Laser Cleaning:
This has been an area or recent research; however, this may result in micro-melting that could impact potential metallographic analysis.
Electrolytic reduction
This was once a frequently used method for the cleaning of archaeological metals it is less commonly used on terrestrial sites where mechanical cleaning has become the preferred method. In this method the object is immersed in an electrolyte solution and a current is run through the object to reduce the corrosion back to metal. It is faster than mechanical cleaning but can result in loss of surface leaving areas that appear pitted or spongy. If the electrolyte solution is not changed regularly, it can also result in redepositing copper on the surface, and in worse cases an object may appear plated.
Chemical cleaning
Though no longer the preferred method for cleaning archaeological metals, many collections have objects that have been cleaned using a variety of cleaning methods. It is important to be aware of these treatment histories as it can impact or limit the objects use for analysis and research as the surface and metal composition may have been altered. Some methods used in the past include boiling in formic acid and cleaning with a paste made up of zinc dust and sulphuric acid [5].
References[edit | edit source]
Use this section for: works cited, bibliography, including websites, external links, etc. Please list references used within the text in alphabetical order, following the JAIC style guide.
Anderson, Gretchen, and Carolyn Riccardelli. "Microclimate storage for metals (and other humidity-sensitive collections): Practical solutions." (2009).
Encyclopedia Britannica. s.v. “Silver.” Last updated: October 15, 2025. https://www.britannica.com/science/silver
Paterakis, Alice Boccia, and Laramie Hickey-Friedman. "Stabilization of iron artifacts from Kaman-Kalehöyük: a comparison of chemical and environmental methods." Studies in conservation 56.3 (2011): 179-190.
Periodic Table. Silver. Accessed October 18, 2025. https://periodic-table.rsc.org/element/47/silver
The Natural Sapphire Company. The History of Silver. Accessed October 18, 2025. https://www.thenaturalsapphirecompany.com/education/history-precious-metals/the-history-of-silver/
Scott, David A. Metallography and microstructure in ancient and historic metals. Getty publications, 1992.
Further reading[edit | edit source]
Use this section for: additional references or resources not cited in the text, external links, etc. For references please follow the JAIC style guide.
Brief annotations are allowed to the extent that the subject dictates.
In regard to Wikipedia articles, for some purposes (particularly academia) Wikipedia may not be an acceptable source, but it does provide an easily accessible online reference. Please see the following article for advise on the appropriate usage of Wikipedia and other encyclopedias: Citing Wikipedia.
This article also explains Wikipedia's "cite tool", which should be used to properly cite an article if it is deemed to be an appropriate reference.
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