Olympic Gold medals must be plated with at least 6 grams of gold.
The specific composition and design of Olympic medals is determined by the host city’s organizing committee. However, minimum standards must be maintained:
Gold and silver medals are at least 92.5% silver.
Gold medals must be plated with at least 6 grams of gold.
All Olympic medals must be at least 3 mm thick and at least 60 mm in diameter.
Bronze medals are bronze, an alloy of copper and usually tin.The silver medals at the 2018 PyeongChang Winter Olympics had a purity of 99.9%, according to Olympic.org. A gold medal was a silver medal plated with 6 grams of gold, while the bronze as made of an alloy of 90% copper and 10% zinc.