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Cosmos » Chemistry » Gold, silver and brass medals

What are the Olympic medals made of? It seems an obvious answer – gold, silver, and bronze; it’s on the label! – but the silver medal is the only one that is actually made from its pure element.

So what are the other medals made of – and what else could you potentially use them for?

Gold medals are not pure gold – that would make them too soft. Instead, they’re pure silver, with six grams of gold plating per medal.

Gold and silver are both very stable elements, with neither reacting with air, but gold is even more stable than silver. If you melted the medal down and soaked it in nitric acid, the silver would react to become silver nitrate but the gold would remain stable, meaning you could separate the two metals out.

A gold medal weighs 556 grams. At a market price of $80 per gram of gold, and $1 per gram of silver, you’re looking at about $1000 of precious metals per medal – $480 of gold, and $550 of silver.

Athletes have been known to sell their gold medals intact, racking up much larger profits – some in the millions – so market value is probably not the best way to make money off a gold medal.

Silver medals are the only ones made of a pure element: they’re all Ag. Weighing in at 550 grams, their purity makes them more chemically useful than the other medals – if you wanted to use the silver for plating a teacup, or designing a better touch screen, you’d just need to heat it to 962°C and melt it down, without any further purification.

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Be warned, though – while it’s not very reactive in pure form, silver becomes much more likely to tarnish once you begin mixing it with other things. Even sterling silver, which is 92.5% pure silver and 7.5% copper (or another metal) tarnishes in air.

Bronze is a very old and well-recognised metal, but it isn’t a pure element, and nor are the bronze medals technically ‘bronze’ – they’re brass.

Bronze is usually an alloy of copper and tin, but bronze medals are an alloy of 95% copper and 5% zinc. This is referred to as ‘red brass’, although industrial red brass, which is used in valves and plumbing, is usually less pure than this, boasting about 85% copper and a mixture of tin, zinc, lead and other metals.

Nevertheless, copper and zinc – while very soft metals themselves – alloy to make a much harder metal. The bronze medal is the hardest and lightest medal (at 450 grams), so it’s probably the best to use as a discus, should you need a discus.

While it’s a bad idea to reuse the metals once they’ve become medals, it’s been a tradition over the past decade to include recycled materials in Olympic medals.

At Tokyo, 100% of the metals in the medals have been recycled. Between 2017 and 2019, people across Japan donated old electronic devices, which had the precious metals extracted from them.

In total, the government collected several million tonnes of equipment, and extracted 32 kilograms of gold, 3500 kilograms of silver and 2200 kilograms of copper and zinc for the bronze medals.

If you’re interested in learning more about recycling metals, we encourage you to take a look at our Briefing on the Circular Economy.

Originally published by Cosmos as Gold, silver and brass medals

Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.

There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.

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