The medals contain 6g of gold, the price of which soared to a record in mid-July thanks to central bank buying, retail interest in China and expectations of easing US monetary policy.

Prices are also substantially higher this year for silver, which makes up at least 92.5% of the weight of gold medals.

Even after adjusting for inflation, the value of medals is still the highest ever, with Olympians benefiting from both the sharp rally in bullion prices and increasingly hefty medals.

In practice, Olympians do not tend to melt or sell their medals, which this year also contain a small piece of the Eiffel Tower.

More lucrative are the gifts that countries give winning athletes, which include cash, exemptions from military service and cows.

Carlos Yulo – who became the Philippines’ first male gold medallist last week – will enjoy a fully furnished condo and a lifetime of free colonoscopies.

Medals that are sold can be worth far more than their metal value.

One of Jesse Owens’ gold medals from Berlin 1936 – when he rebuked Adolf Hitler’s attempt to showcase Aryan racial supremacy – fetched almost US$1.5 million at an auction in 2013.