US-4060385 Crater of Diamonds State Park

Crater of Diamonds State Park is a 911-acre (369 ha) Arkansas state park. The park features a 37.5-acre (15.2 ha) plowed field, the world's only diamond-bearing site accessible to the public. 

Diamonds have continuously been discovered in the field since 1906. The site became a state park in 1972 after the Arkansas Department of Parks and Tourism purchased the site from the Arkansas Diamond Company and Ozark Diamond Mines Corporation, who had operated the site as a tourist attraction previously.   (Source: Wikipedia)

This postcard came from Grace who had visited the Crater of Diamonds State Park in June.  Postcard received on 6 July 2016 (Postcrossing)