Chemistry of Olympics 2012 Medals

Medal Specification : 

Weight :  375-400g

Diameter : 85mm 

Thickness : 7mm 

Composition of Olympics Medals

1. The gold medal  :  92.5% silver and 1.34% gold, with the remainder copper (a minimum of 6g of gold).
2. The silver medal :  92.5% silver, with the remainder copper.
3. The bronze medal is :  97.0% copper, 2.5% zinc and 0.5% tin.

*source from London Olympic Official Website