Coinage metals
Encyclopedia
The coinage metals comprise, at minimum, those metallic chemical element
s which have historically been used as components in alloy
s used to mint coins. The term is not perfectly defined, however, since a number of metals have been used to make "demonstration 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 (for example, zirconium), but their status as coin metals is not clear. In general, because of problems caused when coin metals are intrinsically valuable as commodities, there has been a trend in the 21st century toward use of coinage metals of only the least exotic and expensive types.
Historically, many coinage metals (or alloys) are from the three nonradioactive members of Group 11
of the Periodic table
(copper, silver and gold); however there are many, even for coins made from intrinsically precious metals. Precious metal
s are always used in bullion coin
s and some collectable coins
. Coins not intended for circulation or for intrinsic value have also been made experimentally using an even larger variety of metals, since they function as fiat money
. In general coins intended for circulation must have metal values considerably less than their face values, for reasons discussed below.
properties. Achieving this goal necessitates the use of base metal alloy
s. Some metals like manganese have occasionally been used in coins, but suffer from making the coins too hard to take an impression well (or metals apt to wear out stamping machines at the mint).
A common base metal alloy for everyday coinage is Cupro-Nickel
(also cupronickel
), with varying proportions of copper
and nickel
, most commonly 75% Cu 25% Ni. Cupronickel 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.
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
. 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 pennies (cents) were once made of copper alloys, but since 1982 have been made of copper-clad zinc.
See comprehensive list of elements and alloys in the link below:
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s which have historically been used as components in alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
s used to mint coins. The term is not perfectly defined, however, since a number of metals have been used to make "demonstration 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 (for example, zirconium), but their status as coin metals is not clear. In general, because of problems caused when coin metals are intrinsically valuable as commodities, there has been a trend in the 21st century toward use of coinage metals of only the least exotic and expensive types.
Historically, many coinage metals (or alloys) are from the three nonradioactive members of Group 11
Group 11 element
A Group 11 element is one in the series of elements in group 11 in the periodic table, consisting of transition metals which are the traditional coinage metals of copper , silver , and gold...
of the Periodic table
Periodic table
The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...
(copper, silver and gold); however there are many, even for coins made from intrinsically precious metals. Precious metal
Precious metal
A precious metal is a rare, naturally occurring metallic chemical element of high economic value.Chemically, the precious metals are less reactive than most elements, have high lustre, are softer or more ductile, and have higher melting points than other metals...
s are always used in bullion coin
Bullion coin
A bullion coin is a coin struck from precious metal and kept as a store of value or an investment, rather than used in day-to-day commerce. Investment coins are generally coins that have been minted after 1800, have a purity of not less than 900 thousandths and are or have been a legal tender in...
s and some collectable coins
Coin collecting
Coin collecting is the collecting or trading of coins or other forms of minted legal tender.Coins of interest to collectors often include those that circulated for only a brief time, coins with mint errors and especially beautiful or historically significant pieces. Coin collecting can be...
. Coins not intended for circulation or for intrinsic value have also been made experimentally using an even larger variety of metals, since they function as fiat money
Fiat money
Fiat money is money that has value only because of government regulation or law. The term derives from the Latin fiat, meaning "let it be done", as such money is established by government decree. Where fiat money is used as currency, the term fiat currency is used.Fiat money originated in 11th...
. In general coins intended for circulation must have metal values considerably less than their face values, for reasons discussed below.
Requirements for a coinage metal
Coins that are intended for circulation have some special requirements based on the conditions they will encounter. For example, a coin may be in circulation for up to 30 years, and so must have excellent wear resistance and anti-corrosionCorrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
properties. Achieving this goal necessitates the use of base metal alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
s. Some metals like manganese have occasionally been used in coins, but suffer from making the coins too hard to take an impression well (or metals apt to wear out stamping machines at the mint).
A common base metal alloy for everyday coinage is Cupro-Nickel
Cupronickel
Cupronickel or copper-nickel or "cupernickel" is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater...
(also cupronickel
Cupronickel
Cupronickel or copper-nickel or "cupernickel" is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater...
), with varying proportions of copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
and nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
, most commonly 75% Cu 25% Ni. Cupronickel has a silver color, is hard wearing and has excellent striking properties, essential for the design
Design
Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...
of the coin to be pressed accurately and quickly during manufacture.
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
Face value
The Face value is the value of a coin, stamp or paper money, as printed on the coin, stamp or bill itself by the minting authority. While the face value usually refers to the true value of the coin, stamp or bill in question it can sometimes be largely symbolic, as is often the case with bullion...
. 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
Penny
A penny is a coin or a type of currency used in several English-speaking countries. It is often the smallest denomination within a currency system.-Etymology:...
from this period is 1.5 new-pence. Modern British pennies are now made of copper-plated steel. For similar reasons, American pennies (cents) were once made of copper alloys, but since 1982 have been made of copper-clad zinc.
List of 28 chemical elements used (alone or in alloys) in coins and medals
Some have been used only in private demos. Very common coin metals elements are uncommented.- AluminiumAluminiumAluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
- AntimonyAntimonyAntimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
(Used as alloy agent in one Chinese coin of 1931. Used in medallion medal alloy) - CarbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
(In all steel and iron coins. A few "coal" coins minted in the hyperinflation in post WW I Germany) - ChromiumChromiumChromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
(Used for plating coins and in some rare hard stainless steel coins) - CobaltCobaltCobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....
(Used in medals. A coin in Camaroon is said to be struck in cobalt) - CopperCopperCopper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
- GoldGoldGold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
- HafniumHafniumHafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869. Hafnium was the penultimate stable...
(Fred Zinkann demo coin) - IronIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
- LeadLeadLead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
- MagnesiumMagnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
(Magnesium-aluminum coins are used in India) - ManganeseManganeseManganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
(Some Mn used in U.S. wartime "silver nickels" and the new US dollar coin for similar reasons—attempts to match magnetic and electrical properties of previous nickels, and previous Susan B. Anthony dollars, for vending machines) - MolybdenumMolybdenumMolybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
(Demo coin - Fred Zinkann) - NickelNickelNickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
- NiobiumNiobiumNiobium or columbium , is a chemical element with the symbol Nb and atomic number 41. It's a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite...
(Austria has issued a number of bimetallic 25 euro coins with a niobium center) - PalladiumPalladiumPalladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...
(½ Hau from Tonga (98%) and some bullion coins) - PlatinumPlatinumPlatinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...
- RheniumRheniumRhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion , rhenium is one of the rarest elements in the Earth's crust. The free element has...
(Demo coin - Fred Zinkann) - RutheniumRutheniumRuthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most chemicals. The Russian scientist Karl Ernst Claus discovered the element...
(1967 ½ Hau from Tonga was 98% palladium and 2% ruthenium) - SeleniumSeleniumSelenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
(Alloy medal only, to commemorate BerzeliusBerzeliusBerzelius is a secret society at Yale University named for the Swedish scientist Jöns Jakob Berzelius, considered one of the founding fathers of modern chemistry...
, discoverer of the element) - SilverSilverSilver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
- TantalumTantalumTantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, the name comes from Tantalus, a character in Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion resistant. It is part of the refractory...
(Used in a bimetallic silver-tantalum coin from Kazakhstan) - Tellurium (Hungarian alloy medal only)
- TinTinTin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...
- TitaniumTitaniumTitanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
(Austria has made bimetallic commemorative coins of silver and titanium) - TungstenTungstenTungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
(Alloys are too hard. A few private demos struck only for experimentation) - VanadiumVanadiumVanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
(Experimental private token demo struck, but generally considered too toxic) - ZincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
- ZirconiumZirconiumZirconium is a chemical element with the symbol Zr and atomic number 40. The name of zirconium is taken from the mineral zircon. Its atomic mass is 91.224. It is a lustrous, grey-white, strong transition metal that resembles titanium...
(Experimental private token demo struck)
See comprehensive list of elements and alloys in the link below: