Arkansas could have leased this land to a mining company. Instead, the state maintains it as the only diamond-producing site in the world where the public can search for diamonds in their original volcanic matrix and keep what they find.

Since Arkansas turned this geological oddity into a state park in 1972, visitors have found more than 35,000 diamonds. The park operates on a simple principle that sounds almost too good to exist in modern America: Everything you find belongs to you, no questions asked, no revenue sharing, no fine print. However, finding diamonds is not as easy as it sounds. //

Park staff told Mays that visitors find one or two diamonds daily, so "keep your expectations in check," she writes. Most diamonds discovered are about the size of a paper match head, while a one-carat diamond is roughly the size of a green pea. But even tiny diamonds carry the thrill of discovery. Park staff provide free identification services, examining finds under loupes and confirming whether that glassy pebble is quartz or something more valuable.