The Rio 2016 silver Olympic medal is pictured at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRU1Show moreShow less
Nelson Carneiro, craftsman from the Casa da Moeda do Brasil (Brazilian Mint) works on the Rio 2016 Olympic medal mold in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRU4Show moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) pours molten metal into a mold to prepare the Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRU5Show moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) prepares Rio 2016 Olympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUGShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) prepares Rio 2016 Olympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUJShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) prepares a Rio 2016 Olympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRULShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) checks a Rio 2016 Paralympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUUShow moreShow less
A machine works on a Rio 2016 Olympic medal at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUYShow moreShow less
The Rio 2016 gold Olympic medal is pictured at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRU3Show moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) prepare Rio 2016 Olympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUEShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) puts plates to prepare the Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRTUShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) varnishes a Rio 2016 Olympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUWShow moreShow less
The Rio 2016 bronze Olympic medal is pictured at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRU0Show moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) prepares a Rio 2016 Paralympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUDShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) shows a Rio 2016 Olympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUIShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) takes out gold-plates Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUSShow moreShow less
Workers from the Casa da Moeda do Brasil (Brazilian Mint) prepare the Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRTZShow moreShow less
Nelson Carneiro, craftsman from the Casa da Moeda do Brasil (Brazilian Mint) works on the Rio 2016 Olympic medal mold in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUCShow moreShow less
A sculptress from the Casa da Moeda do Brasil (Brazilian Mint) works on the Rio 2016 Olympic medal at her computer in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUAShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) takes out gold-plated Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUFShow moreShow less
Workers from the Casa da Moeda do Brasil (Brazilian Mint) prepare Rio 2016 Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUHShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) cleans a Rio 2016 Olympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUMShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) cleans a Rio 2016 Olympic medal in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUPShow moreShow less
A worker from the Casa da Moeda do Brasil (Brazilian Mint) takes out gold-plated Rio 2016 Olympic and Paralympic medals in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRUZShow moreShow less
The Rio 2016 Olympic medals are pictured at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. REUTERS/Sergio Moraes - RTX2IRV1Show moreShow less
Making a Rio Olympic medal
The medals that will be awarded at Rio are the most sustainable in Olympic history: much of the silver is recycled from old mirrors and X-ray plates; the gold is free of mercury.