(CNN/KAKE) - A 7-year-old girl got a big birthday present when she found a nearly 3-carat diamond at a state park in Arkansas. 

The Crater of Diamonds State Park is well-known for being a place where visitors can find diamonds. Of course, most don't. But Aspen Brown happened to catch a glimpse of a pea-sized brown diamond near the park's fence line. 

Park officials said it was probably unearthed when a contractor dug a trench in August to help manage erosion in the park's 37-acre diamond search area. 

According to the park's website, more than 35,000 diamonds have been found there since 1972. Aspen's is the second largest discovered this year. 

The Crater of Diamonds State Park is the only diamond-producing site in the world where the public can search for diamonds and keep them. It's about a 7-hour drive from Wichita.

The land was minded by commercial diamond hunters before it was turned into a state park.