Under IOC rules, a gold medal must be made of at least 92.5% pure silver and plated with at least 6 grams of gold. At the Paris 2024 Games, each gold medal weighed 529 grams, of which just 6 grams were gold. It also featured an 18-gram hexagon of iron taken from the Eiffel Tower during renovations. A gold medal's worth lies far more in the achievement than in the metal.
That's the estimate from a WHO-led study published in The Lancet in 2024, covering the half-century since the Expanded Programme on Immunization was launched in 1974. It works out to about six lives saved every minute, mostly infants. The measles vaccine alone accounts for around 60% of those lives.
According to the World Gold Council, about 216,000 tonnes of gold have been mined in all of human history. Because gold is so dense (19.3 tonnes per cubic metre), it would fit in a cube about 22 metres on each side, roughly the height of a seven-storey building. Strikingly, about two-thirds of it has been mined since 1950.