Why are some UK coins magnetic?

From time to time we’re asked the question, ‘Why are some coins magnetic?’ It’s one of those interesting facts that you seem to just stumble across. I discovered it when a loose coin stuck to the back of a fridge magnet in a drawer! So, let’s take a look at the science behind it and some fun facts we found along the way…

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If you were to take a magnet to the ‘smaller’ coins in your change today, you will find that some of them stick. What, I suppose, is interesting about this is that only some of the coins are magnetic… Why aren’t all of them?

A quick Google search will uncover the official explanation, which can be found on both royalmint.com and the Royal Mint Museum’s website. In short, the composition of 1p and 2p coins was changed from bronze to copper-plated steel in 1992 and the composition of 5p and 10p coins was changed from cupro-nickel to nickel-plated steel in 2011. The common denominator? Steel.

The ‘Copper’ 1p and 2p coins were traditionally made from a bronze alloy of copper, tin and zinc. However, since September 1992 they have been made from copper-plated steel. Both types are the same colour, weight, diameter and design and circulate together, but it’s the new copper-plated steel coins that are attracted to magnets. The iron content in the steel core is what makes them magnetic.

'Silver' 5p coins, tumbling out of the presses!
‘Silver’ 5p coins, tumbling out of the presses!

Since January 2012, the ‘Silver’ 5p and 10p coins have also been made from a plated steel, in turn making them magnetic. While they changed more recently than the ‘coppers’, you will actually find that a higher percentage of 5p and 10p coins are magnetic. This is because in 2013 The Royal Mint began a programme to recover old 5p and 10p coins from circulation. Since then some 330 million of the new plated steel coins have been issued in their place.

As people have discovered the magnetic property of the coins in their change, many have tried experimenting to see how far they can push the boundaries of what can be done with them.

This sculpture called ‘Drop’ by Paul Cocksedge, created in 2010, is magnetic and encouraged passers-by to attach their unwanted pennies to its surface in aid of charity. Photos by Susan Smart, courtesy of Paul Cocksedge Studio

magnetism2.inset (1)When plated steel coins are attached to a magnet, the coins themselves become magnetised as the magnetic force travels through them. With a strong enough magnet you’re able to attach coins to each other and ‘dangle’ them and some amazing feats of balance and ingenuity can be achieved.

So, find yourself a magnet and have go! See how many you can balance or stick together and share your finds with us on Facebook or Twitter – we’d love to see how you get on.

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  • Ed_Bastard

    Of course you don’t tell us the real reason for these cheap coins, why would you..proper 2p coins are worth 3.5p and can be weighed in when the ol’ bitch dies.

    • Menelik A I

      Ed Bastard obviously doesn’t remember pre-decimal days. The coins of George VI and George V were in circulation alongside those of Elizabeth II . Before long (about a year) post offices will be selling new stamps when Her Majesty dies, but there will be no special move to replace the coins in circulation. (Older members will remember also a few Edward VII coins still around, and quite a lot of Queen Victoria pennies, mainly from her last ten years or so).

      The idea of coinage being worth in silver or copper the value of the coin was abandoned all over the world a very long time ago, but ideally the value of the metal should not be more than the value of the coin, or they get melted down. However, if Ed is thinking of melting down bronze 2p coins for profit himself (he wouldn’t actually make very much out of it), it won’t make any difference it the Queen is alive or not,

      • Ed_Bastard

        I’m older than you my friend. Yes, once the Monarch has died coins remain in circulation, but my point is they can be melted down since the legal rights of the Queen are no more. And a 100%+ gain is not to be sniffed at.

        • Menelik A I

          Nonsense. The Queen does not have personal legal rights over the coins in circulation. You have got the cost of melting down the coins, and before that the problem finding a factory to do it, considering that if it was worthwhile they could do it themselves without you. Several years ago, a television programme tried to find such a place and make a profit, but it wasn’t at all worthwhile. I think they went to France to avoid legal scruples about melting down any legal tender coins.

          • Ed_Bastard

            The point is; when she’s dead the coins can be weighed in, the metal content outweighs the face value by at least 50% at today’s copper price..

    • ColinEP

      If you are one of those who wishes to melt old coins down, I feel sure that you would not be bothered as to the monarch being dead or alive. Yes the copper content is worth more than the face value but the cost of smelting would out-way the profit. If however you find pre 1920 or pre 1946 silver coins they are worth melting down due to the value of silver (92.5% & 50% silver).

  • Menelik A I

    Strictly speaking the coins are not “magnetic”. If your screwdriver has become magnetic, you can pick up steel screws with it. You can’t do this with the coins. They are simply made of (plated) steel, so they can be picked up with a magnet.

    Nickel can also be picked up by a magnet, but not as easily as steel. This means that you can do interesting experiments with pre-euro French coins (often nickel) and pre-euro Italian coins (often stainless steel). The way in which the magnetism passes through the coin to pick up other coins is different according to whether the coin is nickel or steel. It would spoil it to tell you exactly what happens .

    • Alex

      The technical word for this is ferrous. This means the coins can be affected by a magnetic field and for a short time while the magnet is in contact with the coin, the coin will be a temporary magnet.

      • Menelik A I

        I’m sorry, but nickel is actually non-ferrous. “Ferrous metals” are basically iron and steel, and other alloys containing an appreciable quantity of iron. In chemistry, “ferrous” and “ferric” are simply the adjectives indicating “iron” in a salt, such as ferrous sulphate or ferric sulphate (there is a difference, beyond the scope of this answer).

        The word Alex is looking for is FERROMAGNETIC. The only reasonably common examples of ferromagnetic materials are iron, nickel, cobalt, and of course lodestone (which is a special kind of iron oxide).

        The term “ferromagnetic” is necessary because some materials behave differently and are called “paramagnetic”, these being chiefly magnesium, molybdenum, lithium, and tantalum . Their behaviour is beyond the scope of this answer.

  • Adam

    De-base?

  • Menelik A I

    It’s all nonsense. The Queen does not have personal legal rights over the coins in circulation. If anyone wants to melt these coins down, it doesn’t make any difference if the Queen is dead or not. You have got the cost of melting down the coins, and before that the problem finding a factory to do it, considering that if it was worthwhile they could do it themselves without you.

  • Richard Holladay

    I should like to know whether the modern coinage (magnetic) is still worth the face value when it has begun to rust – I metal detect and am beginning to collect a hoard of rusting 2p and 1p and even 5p coins whereas I can happily dig up pre magnetic decimal and pre decimal coinage in far better condition.
    In salt water the modern 2p and 1p coins corrode away in no time at all !