or silver content. They care that the award hung around Phelps’s neck.

“With awards there is an intrinsic value, but with medals it’s really only what is without any intrinsic value,” said Mike Provenzale, sports production manager at Heritage Auctions. “It’s all about what it is and not what it’s made of.”

Heritage sells a lot of NBA and NFL championship rings loaded with diamonds and gold. Those do have intrinsic value, Provenzale said. As a gaudy ring, it’s probably worth $10,000.

But buyers will spend $20,000 on them: half for the cost of the materials, half because they really love their favorite teams.

Olympic medals, even vintage medals, don’t work like that. Heritage is selling a diving medal from the 1936 games in Berlin. It’s intrinsic value, adjusted for 2016 gold and silver prices, is less than $100. Provenzale still expects it to sell at auction at the end of the month for more than $20,000.

Now is the time to sell Olympic memorabilia, appraisers say. Collectors are excited about the games capturing people’s imagination worldwide. In a month, they won’t have the same pull. Then NFL football season starts.

So Olympians, if you’re reading, this is the moment to hit the auction block.