A built-in rattle is the surprise addition to the brand new 2016 Paralympic medals. When shaken, each medal has a slightly different metallic sound; with gold having the loudest, down to bronze with the subtlest.

The idea is that this will give visually impaired athletes another way to distinguish between the medals, aside from the braille writing. The manager in charge of the sound element, Victor Hugo Berbert, said he hopes the design would catch on.

"Our hope, and the I think it's the Olympic Committee's hope too, is that this becomes the style. That the next games bring other sensory elements for the athletes and that this might carry on. That's what we hope, so that Paralympic athletes can have their own commemoration. To not just be able to show the medal, but for those who have a visual or sensory impairment to be able to feel it not just by touching it, not just with the Braille that is on it, but with its sound," Berbert said.

According to the mint, which is producing the medals, a total of 5,130 medals, 2,488 for the Olympics and another 2,642 for the Paralympics are being created for the games, in a joint effort with the Rio 2016 Olympic Committee.

For those making the medals, the excitement is building for them to see their crafted masterpieces on show. "It will be a feeling of conquest for sure. We work hard and then to see it on the athletes' chests is a big deal because very few of them (athletes) are going to win, a lot will compete and just a few will reach that, so this is a big deal for us too. To know that the medals are highly valued," said an engraver at the mint, Nelson Neto Carneiro.

The medals, certificates, packaging and other materials associated with the Olympic medals being produced at the mint will come with an official seal from the Forest Stewardship Council (FSC) assuring the materials were produced in an environmentally sustainable manner, the mint has said. The superintendent for environmental and quality control at the mint, Marcos Pereira, has claimed that the Rio 2016 medals will be the most sustainable prizes ever awarded at an Olympics.

"The gold is 100% extracted without the use of mercury, 30% of the silver is from recycled material. And the copper used in the bronze medals also uses 30% recycled material from the Casa da Moeda do Brasil (mint) itself. When you look at everything including the ribbons, containers and the diplomas and everything else, we can consider these to be the most sustainable medals in Olympic history," Pereira said.

New Rio 2016 medals reviled
New Rio 2016 medals said to be the most sustainable prise awarded at an Olympics. Reuters