Coinage metals

Coinage metals
The coinage metals comprise those metallic chemical elements and alloys which have been used to mint coins. Historically, most coinage metals are from the three nonradioactive members of group 11 of the periodic table: copper, silver and gold. Copper is usually augmented with tin or other metals to form bronze. Gold, silver and bronze or copper were the principal coinage metals of the ancient world, the medieval period and into the late modern period when the diversity of coinage metals increased. While coins are primarily made from metal, some non-metallic materials have also been used.
History
Early coinage made from metal came into use during the Axial Age in the Greek world, in northern India, and in China, as coins became a widespread embodiment of money.
Bronze, gold, silver and electrum (a naturally occurring pale yellow mixture of gold and silver that was further alloyed with silver and copper) were used. Silver coins from about 700 BC, are known from Aegina Island.
Early electrum coins from Ephesus, Lydia date from about 650 BC. Ancient India in 6th century BC, was also one of the earliest issuers of coins in the world.
The gold Croeseids, issued in Lydia, were the first true gold coins with a standardized purity for general circulation. The gold and silver Croeseids formed the world's first bimetallic monetary system, c. 550 BC.
The Persian daric was also an early gold coin which, along with a similar silver coin, the siglos, (from Ancient Greek σίγλος, Hebrew שֶׁקֶל (shékel)) represented the bimetallic monetary standard of the Achaemenid Persian Empire. These coins were also very well known in the Persian and Sassanids era, most notably, in Susa and in Ctesiphon.
Precious metals were used historically in commodity money and are found in bullion coins and some collectable coins. Coins functioning as fiat money are now made from a larger variety of base metals.
Requirements for a coinage metal
Coins that are intended for circulation may circulate for decades and thus must have excellent resistance to wear and corrosion. Achieving this goal typically necessitates the use of base metal alloys. In addition, some metals, such as manganese, are unsuitable as they are too hard to take an impression well or are apt to wear out stamping machines at the mint.
When minting coins, especially low denomination coins, there is a risk that the value of metal within a coin is greater than the face value, leading to negative seigniorage. This leads to the possibility of smelters taking coins and melting them down for the scrap value of the metal. Pre-1992 British pennies were made of 97% copper; but as of 2008, based on the price of copper, the value of a penny from this period is 1.5 new-pence. Modern British pennies are now made of copper-plated steel. For similar reasons, American cents were once made of copper alloys, but since 1982 have been made of copper-plated zinc.
Cupronickel, a common base metal alloy with varying proportions of copper and nickel, was introduced as a cheaper alternative for silver in coinage. Cupronickel, most commonly 75% copper, 25% nickel, has a silver color, is hard wearing and has excellent striking properties, essential for the design of the coin to be pressed accurately and quickly during manufacture. However, in the 21st century with the prices of both copper and nickel rising, it has become common to experiment with various alloys of steel, often stainless steel as an even cheaper alternative. For example, in India some coins have been made from a stainless steel that contains 82% iron, 18% chromium, and many other countries that have minted coins that contain metals now worth nearly the coin face-value, are experimenting with various steel alloys. Italy had earlier experimented with acmonital, a stainless steel alloy, for its coins
A number of more exotic metals have been used to make demonstration or fantasy coins which have never been used to make monetized coins for any nation-state, but could be. Some of these elements would make excellent coins in theory (e.g. zirconium). More expensive metals that are intrinsically valuable as commodities are less practical as coinage due to their cost, but could be used for bullion.
Chemical elements used in circulating coins
In 1992, twenty-four chemical elements used in world coinage were documented by Jay and Marieli Roe in an award-winning exhibit and publication: aluminum, antimony, carbon, cobalt, copper, gold, hafnium, iron, lead, magnesium, molybdenum, nickel, niobium, palladium, platinum, rhenium, silver, tantalum, tin, titanium, tungsten, vanadium, zinc and zirconium. Chromium and manganese, however, were not mentioned, even though both elements had been used in common circulation coins (Canada wartime V nickels and US wartime Jefferson nickels, respectively) long before the article's publication.
Non-circulating
Chemical elements used in non-circulating (commemorative, demo, bullion or novelty) coins, medals, patterns, and trial strikes:
Cadmium: 1828 medal made by G. Loos for the marriage of Heinrich von Dechen, "of Silesian cadmium".
Cobalt: 2005 Cameroon 750 CFA francs struck in cobalt-plated iron.
Hafnium: Fred Zinkann demo coin.
Iridium: 2013 oz 10 franc bullion coin issued by Rwanda as part of "Noble Five" precious metals set.
Molybdenum: Demo coin, Fred Zinkann. Mintage 250-1 tr oz coins 2008 by Coins By Design, Murray Buckner.
Niobium: Austria has issued a number of bimetallic 25 euro coins with a niobium center.
Palladium First issued 1966 by Sierra Leone. Also presentation sets from Tonga, bullion coins of various countries.
Rhenium: Fred Zinkann fantasy pieces, Pope Matthew Triple Ducat and Malvinas 5 Australes
Rhodium: 2014 oz 10 franc bullion coin issued by Rwanda as part of "Noble Six" precious metals set. Also Cohen Mint bullion round.
Ruthenium: 1967 Hau from Tonga was 98% palladium and 2% ruthenium.
Selenium: 1862 medal in UK Science Museum, commemorating Berzelius, discoverer of the element.
Silicon: Privately struck US quarter patterns dated 1964 (Pollock-5380) in nickel-silicon alloy.
Tantalum: Used in a bimetallic silver-tantalum coin from Kazakhstan.
Tellurium: 1896 Hungarian mining medal. Reproductions exist from 1975.
Titanium: First issued 1999 by Gibraltar. Austria has made bimetallic silver/titanium commemoratives.
Tungsten: Tungsten alloys are too hard. A few private demos struck only for experimentation. Fred Zinkann US half eagle patterns.
Uranium: Two types of a German medal of native uranium.
Vanadium: Mintage 20-1 Troy ounce coins 2011 by Coins By Design, Murray Buckner.
Zirconium: Mintage 500-1 Troy ounce coins 2012 including 50 black & 50 Rainbow by Coins By Design, Murray Buckner.
Element Series
Beginning in 2006, Dave Hamric (Metallium) has been attempting to strike "coins" (technically tokens or medals, about the size of a US cent) of every stable chemical element. He has struck tokens of the following elements, apparently not only metals:
Aluminium,
Antimony,
Barium (reactive, sealed in glass capsule),
Beryllium,
Bismuth,
Boron (mixed with binder, sealed in resin cast),
Cadmium,
Calcium (reactive, sealed in glass capsule),
Carbon (mixed with binder, sealed in resin cast),
Cerium (reactive, sealed in glass capsule),
Chromium,
Cobalt,
Copper,
Dysprosium,
Erbium,
Europium (reactive, sealed in glass capsule),
Gadolinium,
Gallium,
Gold,
Hafnium,
Holmium,
Indium,
Iridium,
Iron,
Lanthanum (reactive, sealed in glass capsule),
Lead,
Lutetium,
Magnesium,
Mercury (sealed in resin cast),
Molybdenum,
Neodymium (reactive, sealed in glass capsule),
Nickel,
Niobium,
Palladium,
Phosphorus (mixed with binder, sealed in resin cast),
Platinum,
Praseodymium (reactive, sealed in glass capsule),
Rhenium,
Rhodium,
Ruthenium,
Samarium (reactive, sealed in glass capsule),
Scandium,
Selenium,
Silver,
Strontium (reactive, sealed in glass capsule),
Sulfur,
Tantalum,
Tellurium,
Terbium,
Thallium (extremely poisonous; lead token clad on one side with thallium foil and sealed in resin),
Thulium,
Tin,
Titanium,
Uranium (not offered for sale),
Vanadium,
Ytterbium,
Yttrium,
Zinc,
Zirconium.
Non-metallic materials used for circulating coins
See also
Billon
Fineness
Italma
Melchior
Nickel silver
Nordic Gold
References
External links
Comprehensive list of metals and their alloys which have been used at various times, in coins for all types of purposes.
Site of coinage metals and alloys