Bi-metallic coins, also part of the mixed metals category, are those which are made from two (bi) metals or alloys. While there are differing types, the most common arrangement features an outer ring with contrasting centre. Common examples in circulation include the British £2 as well as €1 and €2.
The earliest known examples date back to the 17th century, and during the Roman Empire large medallions with bronze or copper centres and contrasting outer rings were issued on special occasions.
For coins in circulation, bi-metallic coins tend to be reserved for high denominations and are used primarily to help prevent counterfeiting as they are more expensive and challenging to mass produce.
Types of bi-metal coin
An early method of producing bi-metal coins was to coat a metal core with another metal. This process originally started as a way to disguise debased coinage – which is the practice of lowering the value of a currency by reducing the amount of precious metal in a coin while continuing to circulate it at face value. This was a frequent practice carried out by government in order to inflate the amount of currency in circulation.
In England during the reign of King Charles I, a series of royal farthing tokens were issued. These farthings were made from copper rod with a wedge of brass hammered into a groove that had been cut into the rod. Blanks were then sliced from the rod and farthings struck from the blanks.
As these coins had a rose on the reverse (instead of a harp as was typical for the time), they are usually referred to as rose farthings.
In England, after King Charles II there was a major reform to currency, including the issue of copper halfpennies and full weight farthings. However, with the price of tin falling and resulting in an industry crisis the decision was made to strike all halfpennies from tin. To help prevent counterfeiting, a square copper plug was inserted into the centre of blanks before striking.
Cladding is when two metals are bonded together, allowing for cheaper metal to be used as a filler. It’s often achieved by passing two sheets of metal through a pair of rollers under sufficient pressure to bond the layers together.
The U.S. Mint was the first to strike a silver centre cent back in December of 1792. Each was handmade at the Mint with workman first making the copper blank, punching out a small whole and then inserting a silver plug before the coins were struck.
A bimetallic coin with an outer ring is where a coin has a large core of one metal with the ring of another. These types of coin are relatively common in today’s circulation. When these coins were first introduced there was a concern they wouldn’t stand the test of time with many worrying they would fall apart.
In actual fact this type of coinage is very sturdy with the manufacturing process of striking bi-metallic coins sealing the centre to the outer ring in a method not dissimilar to tongue and groove.
Sample coins were tested to see what tonnage of pressure is required to pop the centre out and the force required to expel the inner ring would in-fact destroy the coin.
Our favourite bi-metal coins
Here at Pobjoy Mint we have a varied selection of bi-metal coins. We featured our top three picks below:
Queens 90th Birthday: 90 Shaped Coin – 2016 Nickel Silver and Bronze $1
Her Majesty Queen Elizabeth II celebrates two birthdays each year, her actual birthday on 21st April and her official Birthday on 10th June. To commemorate her 90th Birthday Pobjoy Mint produced a new coin on behalf of the British Virgin Islands with the unique shape of the number 90.
To highlight the unique shape of the coin we have included a bouquet that covers its surround by showing the Rose of England, the Thistle of Scotland, the Daffodil of Wales and the Shamrock of Ireland, which represent the four countries that make up the United Kingdom.
This 2016 Nickel Silver & Bronze $1 Coin was issued on behalf of the British Virgin Islands and comes in a unique presentation box that plays the National Anthem. You will also receive a Certificate of Authenticity.
This coin is also available as Fine Silver Gold Plated.
Falkland Islands 2014 - Commemorating the Battle of the Falkland Islands - Bi-Metal Coin
This coin was issued on behalf of the Falkland Islands to commemorate the Centenary of the Battle of the Falkland Islands.
The design on the coin features the fast light cruiser HMS Glasgow, one of the key ships in the battle, surrounded by bomb water explosions and the date of the battle.
Available in Base metal, this bi-metallic coin features an effigy of Her Majesty Queen Elizabeth II, Lord of Mann, by Ian Rank-Broadley FRBS.
Isle of Man 2011 - Celebrating the Commonwealth Youth Games - Bi-Metal Coin
In September 2011, the Isle of Man hosted more than 70 nations when the fourth Commonwealth Youth Games was held on the Island. To commemorate this sporting event, Pobjoy Mint issued a new £2 circulating coin on behalf of the Isle of Man Treasury.
The new £2 collector's coin features the official Commonwealth Youth Games Mascot, Tosha the Cat along with the official logo of the games. The name Tosha has the appropriate Manx Gaelic meaning of ‘First’.
Available in base metal, the IOM coin features an effigy of Her Majesty Queen Elizabeth II, Lord of Mann, by Ian Rank-Broadley FRBS.