Olympic gold medals are required to be made of sterling silver covered with at least 6 grams of pure gold, according to About.com. Each gold medal must have a diameter of at least 60 millimeters.
The tradition of giving gold, silver and bronze medals to the winners of Olympic events began with the third modern Olympic Games in 1904 in St. Louis, Mo. Initially, the medals were made of solid gold; however, the last time solid gold medals were given out at the Olympics was at the 1912 Olympics in Stockholm. Each Olympic medal must have the name of the sport for which it was won written on the medal.