Olympics 2016: Everything You Need to Know About Gold Medals

— -- Winners biting down on their gold medals has become the classic post-competition pose at the 2016 Summer Olympics in Rio.

The reason for biting down? It’s an old method of testing whether a metal is pure, but science doesn’t necessarily back the trend. Olympic gold medals haven’t been made of solid gold since 1912, after World War II caused shortages in the precious metal.

Today, Olympic gold medals contain only about 1.34 percent gold, with the rest composed of sterling silver.

According to Forbes magazine contributor Anthony DeMarco, the medals themselves are “the most sustainable ever made.”

DeMarco told ABC News that the silver is "30 percent recycled, using mirrors, X-ray plates and other kinds of refuse." At the current market prices for gold and silver, the price of the medal is about $564.

Even if the 812 gold medals that will be awarded at these games aren’t solid gold, recipients shouldn’t be too disappointed. Many countries award additional prizes to the top medal winners as well. For example, Kazakhstan gives each of its gold medalists $250,000. Malaysia gives its gold-medal winners a bar of solid gold.

U.S. athletes earn $25,000 for winning gold. It’s taxed by the government as income earned abroad.

Beyond the so-called podium value, some medals wind up being worth far more. One of the four track and field gold medals Jesse Owens won at the 1936 Summer Games in Berlin was sold at auction for $1.47 million in 2013.

"The important thing about the increased value is the stories behind them," Demarco Said. "Michael Phelps ... could be one of the best stories in Olympic history so you know that those medals are going to go for very high value."