If there's one thing we've always taken for granted regarding the Olympics, it's that gold medals are actually made out of gold. So imagine our surprise when we learned that this year's first place medals are mostly silver.

Although organizers of the 2012 London Olympic games have touted their gold medals as the heaviest in history, they're 92.5% silver, with a thin coating of gold totaling only six grams. Given the current price of gold and silver, each medal would only fetch around $620 on the current market.

"They made this coin larger than any other Olympics ever have. But you can make a gold coin fairly large if you’re just going to plate whatever’s underneath it with gold," said Kevin DeMeritt, founder of LA-based precious metals company Lear Capital. "So it’s a beautiful coin .... But most of the coin is silver which really doesn’t add up to a whole lot."

Pure gold medals haven't been awarded to athletes since the 1912 games in Stockholm. By comparison, those medals are worth $1,207 today in raw gold.

In fact, DeMeritt predicts that future gold medals will be even less valuable. "Who knows?" he said. "Maybe they'll just use copper (worth $3.35 a pound) and then plate it with gold."

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