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Mexico Still Uses Silver Coins & Coin Composition

Mexico is the only country that uses silver coins for its currency, as of 2015. The silver used in Mexican currency is in minute amounts, with other metals such as nickel and copper more commonly found. Coins used to be made of silver and gold, over the years they have been debased, the gold and silver went from 92% to 50% to 2% and finally no gold or silver in coins. It seems unimaginable today that gold and silver would be used for coinage. Here are some of today's coins and their composition.

Australia

Australia's 5c, 10c, 20c and 50c coins are 75 per cent copper and 25 per cent nickel. The $1 and $2 coins are made from 92 per cent copper, six per cent aluminium and two per cent nickel. The only Australian coin to be withdrawn from circulation because of the cost of its metal content was the 1966 silver 50c.

The choice of composition is price of metal, and it durability for example brass, which is made by melting copper and zinc together, is harder, stronger, more corrosion resistant and has an attractive gold colour. It still keeps its anti-bacterial properties, which makes it a great material for door knobs, handrails and plumbing fittings.

USA

Denomination Cent

2017 Lincoln Penny Uncirculated Obverse Philadelphia
Nickel

2017 Jefferson Nickel Uncirculated Obverse Philadelphia
Dime

2017 Roosevelt Dime Uncirculated Coin Obverse Philadelphia
Quarter Dollar

2017 America the Beautiful Quarters Coin Uncirculated Obverse
Half Dollar

2017 Kennedy Half Dollar Uncirculated Coin Obverse Philadelphia
Dollar

2018 American Innovation One Dollar Uncirculated Coin Obverse
Composition Copper Plated Zinc

2.5% Cu
Balance Zn

Cupro-Nickel

25% Ni
Balance Cu

Cupro-Nickel

8.33% Ni
Balance Cu

Cupro-Nickel

8.33% Ni
Balance Cu

Cupro-Nickel

8.33% Ni
Balance Cu

Manganese-Brass

88.5% Cu
6% Zn
3.5% Mn
2% Ni

Weight 2.500 g 5.000 g 2.268 g 5.670 g 11.340 g 8.1 g
Diameter 0.750 in.
19.05 mm
0.835 in.
21.21 mm
0.705 in.
17.91 mm
0.955 in.
24.26 mm
1.205 in.
30.61 mm
1.043 in.
26.49 mm
Thickness 1.52 mm 1.95 mm 1.35 mm 1.75 mm 2.15 mm 2.00 mm
Edge Plain Plain Reeded Reeded Reeded Edge-Lettering
No. of Reeds N/A N/A 118 119 150 N/A

UK

In the wake of the recent announcement of a new £1 coin to be introduced in 2017, look at some of the metals present in the coins of the United Kingdom. All of these coins are produced using alloys, or mixtures of metals; the main metals used include copper, nickel, zinc and iron. The composition of some of the coins has also changed since their original introduction.

The three main alloys used in the manufacture of coins are nickel-brass (mainly copper, with zinc and nickel), cupronickel (mainly copper, with nickel), and bronze (mainly copper, with zinc and tin). Copper and its alloys can be easily made into coins, and also show good resistance to corrosion. Additionally, they are also natural antimicrobial materials, due to their toxic effect on moulds, viruses & fungi, a characteristic which is highly beneficial considering that currency changes hands frequently.

Until recent years, copper was also chosen due to its relative cheapness. However, as its wide range of applications has increased demand, the price of copper has risen in recent years, to the point where some low value coins have become worth less in monetary terms than their copper content. As a consequence, several British coins have undergone changes in composition since their introduction, in order to minimise copper content.

1p & 2p coins, formerly composed of 97% copper content, have, since 1992, been made from copper-plated steel. Steel is an alloy of iron with small amounts of carbon (and trace amounts of manganese). The coating of copper on the steel core is just 0.025mm thick, vastly reducing the percentage of copper contained within the coin. Similarly, 10p and 5p coins, formerly fashioned from cupro-nickel, are now made from nickel-plated steel, cutting out the inclusion of copper entirely.

coin_composition.txt · Last modified: 2022/07/01 11:23 (external edit)