The amount of gold in an Olympic gold medal has fallen to 1.34 percent, thanks to gold prices that recently peaked at $1,895 an ounce. At current prices, a pure 400g medal would cost about $25,000 to make, with a total bill of about $50m for the games.

"The last time the Olympic Games handed out solid gold medals was a hundred years ago at the 1912 Summer Games in Stockholm, Sweden," writes gold brokers Dillon Gage. "Gold medals were in fact only gold for eight years. The 1904 Olympics in St. Louis introduced the gold medal as the prize for first place."

The 2012 gold is 92.5 percent silver, 1.34 percent gold, and 6.16 copper, with IOC rules specifying that it must contain 550 grams of high-quality silver and 6 grams of gold. The resulting medallion is worth about $500. For the silver medal, the gold is replaced with more copper, for a $260 bill of materials.

The bronze medal is 97 percent copper, 2.5 percent zinc and 0.5 percent tin. Valued at about $3, you might be able to trade one for a bag of chips in Olympic park if you skip the fish.