Cochise College Student Papers in Geology
Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
wellerr@cochise.edu
Gold, Silver, Copper
Simara Hubble
Physical Geology
Fall 2005
Image Courtesy of Stan Celestian Glendale Community College |
Gold, element Au, has been known to mankind for thousands of years, or as most sources claim, since “ancient times”. Its value has stood the test of time and its uses have progressed from monetary and decorative to industrial and technological. |
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Gold Ore:
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U.S. domestic gold mining production was 353 tons in 2000 and 247 in 2004 (USGS). Dominant gold producing areas in the United States are Nevada, Alaska, California, South Dakota, Colorado and the Sierra Nevadas. Globally dominant gold mining areas are South Africa, China, Russia and Australia.
Most well known is the use of gold as money, a medium of exchange for the past three thousand years (The Privateer). This use was due in large part to its durability, common appeal, and scarcity, among other factors, all of which are necessary for a material to be used as a medium of exchange as defined by The Privateer. Contrary to what one might assume, gold has not been used as a reserve currency since 1971 (The Privateer). The reason being is that there is simply not enough of it to accommodate the global markets of the world’s industrially advanced economies and less developed economies do not have access to it at all (The Privateer). The concept of paper money can be traced in part to paper “receipts” that goldsmiths would issue in return to commercially storing gold for those who owned it (The Privateer).
Image Courtesy of Brooks R. Dillard YupRocks.com |
Copper, Cu, the second element focused on in this report has been key to the evolutionary progress of mankind since prehistoric times. Pure copper has been used for weapons and decoration, and the discovery of strengthening it by creating alloys has propelled civilizations into new eras. |
Image Courtesy of Roger Weller Cochise College |
Basaltic Lavas:
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Bingham Canyon in Utah still produces copper, although it the low grade copper ore discovered there has been mined for over a hundred years (www.unr.edu).
U.S. domestic copper mining production was 1,450 tons in 2000 and 1,160 in 2004 (USGS). Arizona is still the largest copper producer in the United States. Utah, New Mexico, Montana and Nevada contribute to the majority of production as well (www.unr.edu). More dominant than the United States in mining production is Chile, with Peru and Indonesia a close third, then fourth.
Economic Uses:
Less dense than gold and silver, copper has found the most practical uses in society. Like gold, it is also malleable, ductile and sectile. “A copper bar 4 inches thick can be heated, rolled, then drawn into a round wire so thin that it is thinner than a human hair” (www.unr.edu). In ages past, it has been used as weaponry, utensils and decoration. Now it is still primarily used for its electrical conductivity. “60% of copper is used in electrical and electronic goods” (School Science). Copper is also used for motors, appliances, plumbing, utensils, coinage and communications. Bronze and brass are both useful alloys of copper, combined with tin and zinc, respectively. Copper has also been used as money, although it never achieved the value of gold or silver.
The Copper Industry:
The average price per pound of copper in 2004 was $1.32 (domestic producers), and $1.28 (London Metal Exchange) (USGS). In 2000, the average price was 88 cents (domestic producers) and 82 cents (London Metal Exchange) (USGS). Regardless of the continued mining and refining of copper and copper ore, the demand is exceeding the current supply, according to the USGS. Given copper’s individual uses for nearly every aspect of our daily lives, this is not surprising. As developing countries are able to advance industrially, this demand will only increase. Acceptable substitutes for copper are used, such as aluminum, steel and plastic. These materials, however, cannot rival the superior heat and electrical conductivity of copper.
Image Courtesy of Brooks R. Dillard YupRocks.com |
Silver, element Ag, is the most electrically and thermally conductive metal known. Discovered by mankind not long after copper and gold, it has been used for thousands of years in ornaments and utensils, and has had an important role in the chemical and photographic industries. Where is it found?
Like the other precious metals discussed, occurrences of native silver are rare in our current age. In fact, according to the Silver Institute, silver is normally found unintentionally as a “plus” while mining for other base metals.
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For the most part, silver is commonly produced as a by-product in mining. According to the Silver Institute, 32% of world silver production was due to its occurrence in lead and zinc ore. The U.S. produced 1,860 tons of silver and 1,200 in 2004 (USGS). The leading silver producing states are Alaska, Nevada, Arizona and Michigan. Globally, the dominant silver producing areas are Mexico, Peru, Australia, China and Poland (The Silver Institute) for 2004.
Image Courtesy of Roger Weller Cochise College |
Silver serves many uses in industrial technology. Silver coated steel bearings are used in jet engines. Silver is also malleable, ductile and sectile, in fact, it sometimes crystallizes in nature as delicate wires. It is also catalytic, bactericidal, photosensitive (silver halides), highly reflective, non-corrosive (the tarnish associated with silver does not affect its commercial uses for the most part) and the most thermally and electrically conducive metal. Silver halides are photosensitive, and are used on photographic film. The invention of the digital camera however, is lessening the demand for conventional cameras. Silver’s catalytic properties are used to create the chemicals formaldehyde and ethylene oxide used in the beginning stages of plastic production. Silver is also used in jewelry, tableware, mirrors, electrical and electronic products, batteries, dental technology, water purification and coinage. |
Silver, while not used as a reserve currency in most countries, is still used as a medium of exchange in the form of coins. In the U.S., we have the silver dollar, more a collector’s items than money and in Africa or the Middle East, silver coins are also used in place of paper money when acceptable. Mexico still uses silver as an official part of its currency. According to The Silver Institute, most countries used silver as money for day-to-day purchases, until the increasing amount of gold available lessened the demand for it.
It is clear that these precious metals are not merely tools used by our ancestors in their early civilizations. These are not merely ornaments that you wear on your wrists, fingers and ears. They have many applications, uses integral to objects we use without consideration to the inward components. They will continue to be useful to mankind; indeed, the only concern with these metals is in the continuance of their production.
Sources Referenced
