John Huddleston noticed unusual stones in his Arkansas pig field in 1906. He thought they might be valuable; a jeweler confirmed they were diamonds. The volcanic pipe beneath his farm had been pushing diamonds to the surface for 100 million years, waiting for someone to notice. Today, Crater of Diamonds State Park lets anyone dig in that same field - for a small admission fee, you can take home whatever you find. Over 35,000 diamonds have been discovered since the park opened in 1972. Most are small, but not all: the 'Strawn-Wagner Diamond,' found in 1990, weighed 3.09 carats rough and was cut to a flawless 1.09-carat gem. The only public diamond mine on Earth sits in a plowed field in rural Arkansas.
A hundred million years ago, a volcanic eruption punched through the Arkansas surface, bringing with it material from deep in the Earth's mantle - including diamonds formed under the immense pressure and heat 100 miles below. The volcanic pipe, called a lamproite, is one of only a handful of diamond-bearing formations ever found in North America. The volcano eroded away; the diamonds remained, concentrated in the 37-acre field where the pipe surfaces. Each rain washes new specimens to the surface. The plowing that park staff conduct regularly turns up stones that have waited since the Cretaceous for someone to pick them up.
The park averages about 600 diamonds per year - two per day - found by visitors willing to crawl through plowed soil looking for translucent crystals. Most are small, a quarter carat or less. But significant stones emerge regularly. The 'Uncle Sam Diamond,' found in 1924 before the park era, weighed 40.23 carats - the largest diamond ever found in the United States. The 'Strawn-Wagner Diamond,' cut to a perfect D-flawless 1.09 carats, proved that Arkansas diamonds match the finest from anywhere. In 2020, a visitor found a 9.07-carat gem, the park's fifth-largest ever. The probability of finding a significant diamond is low; the possibility keeps people digging.
Diamond hunting at Crater of Diamonds is democratic - no training required. The park provides basic equipment: screens for sifting, boxes for washing soil. Experienced hunters bring their own tools: shovels, buckets, knee pads. The technique varies: 'dry sifting' after rain when diamonds wash to the surface, 'wet sifting' with water to separate heavy stones, 'surface searching' by crawling and looking. The diamonds here are typically translucent white, yellow, or brown, with the distinctive adamantine luster that marks true carbon crystal. Park staff help identify finds, certifying genuine diamonds for owners who want documentation.
Unlike most diamond mining, Crater of Diamonds involves no ethical concerns about labor practices or conflict finance. The diamonds are found by visitors who pay admission and keep what they find - no middlemen, no trade chains, no questions about origin. The park is the only source for diamonds that can be definitively traced to American soil. For couples seeking conflict-free engagement rings, the romantic appeal is obvious: stones found by the wearer, in American soil, with no exploitation involved. The diamonds are modest by commercial standards, but their provenance is unimpeachable.
Crater of Diamonds State Park is located near Murfreesboro in southwestern Arkansas, about 120 miles from Little Rock. The search field is open year-round; hours vary seasonally. Admission is charged; all equipment can be rented on-site. The plowed field covers 37 acres; comfortable clothes, sunscreen, and patience are essential. The park offers identification services for potential finds. The Diamond Discovery Center explains the geology and displays notable finds. Nearby attractions include Little Missouri Falls and the town of Murfreesboro's antique shops. The experience combines outdoor activity with treasure hunting - the only place on Earth where a public visitor can dig for diamonds and legally keep them.
Located at 34.03°N, 93.67°W in southwestern Arkansas, about 120 miles southwest of Little Rock. From altitude, the park appears as a plowed field - 37 acres of bare earth distinctly different from the forested surroundings. The diamond field is the exposed surface of an ancient volcanic pipe, the only productive diamond source in the United States. The town of Murfreesboro lies nearby. The Little Missouri River traces to the southwest. What appears from altitude as a simple plowed field is the only public diamond mine on Earth - the surface of a 100-million-year-old volcano that delivers diamonds to anyone willing to dig.