A factory in Santa Cruz, about 70 kilometres (43 miles) from the centre of Rio de Janeiro, unveiled how unique Olympic medals were made on Thursday.Once the design of the Rio Olympic medals was set, the factory workers carved a plaster cast by hand, which would then be used as a model for the final pieces. Factory workers used pressing machines to create the coveted symbols of victory. Gold medals went through an extra step called the "gold bath." The gold medal, valued at $590 (€529), is actually made of 494 grams (17 ounces) of silver and only six grams (0.2 ounces) of gold. The last time Olympic medals were made of solid gold was during the 1912 Olympic Games in Stockholm.