An 8.52-carat diamond was discovered in Arkansas' Crater of Diamonds State Park on Wednesday.

On Wednesday June 24th Crater of Diamonds State Park visitor Bobbie Oskarson of Longmont, Colorado uncovered an 8.25-carat diamond. The stone is the fifth-largest diamond found by a visitor to the state park since the site was established in 1972.

At first she thought the diamond was a quartz crystal because of its size and shape, but a park staffer confirmed later that it was indeed a diamond.

"Ms. Oskarson and her boyfriend Travis Dillon saw the Crater of Diamonds State Park on an Arkansas highway map while in the nearby town of Hot Springs and decided to visit the park. And what a lucky first visit it was for her!" park interpreter Waymon Cox said in a press release.

Oskarson named her find the Esperanza Diamond, after her niece, and plans to keep the gem.

More than 30 diamonds have been discovered in the park's search area this year. Cox said above-normal rainfall this year is one reason for the frequent finds.

"Rain, plus the regular plowing of the search field by our maintenance staff, increases visitors' chances of finding diamonds in the search area," he said.

More than 75,000 diamonds have been unearthed in the park since the first diamonds were discovered there in 1906.

The largest rough diamond ever discovered in Crater of Diamonds State Park (and the largest ever found in the United States) is the Uncle Sam Diamond, which was found in 1924 and was a hefty 40.23 carats, according to the park website.

Kathleen Marino M.A, G.G., AJP, NAJA

Australian scientists said Wednesday that they have uncovered a "very rare" 2,000-year-old natural sea pearl while excavating a remote coastal Aboriginal site. The pearl is the first found on the continent.

Australia's University of Wollongong on June 3, 2015: a "very rare" 2,000-year-old natural pearl (the first found on the vast island continent) uncovered while excavating a remote coastal Aboriginal site — Australia's University of Wollongong on June 3, 2015: a "very rare" 2,000-year-old natural pearl (the first found on the vast island continent) uncovered while excavating a remote coastal Aboriginal site

Kat Szabo, an associate professor at the University of Wollongong said that archaeologists came across the pearl while excavating the site on the north Kimberley coast of Western Australia.

"Natural pearls are very rare in nature and we certainly -- despite many, many (oyster) shell middens being found in Australia -- we've never found a natural pearl before," Szabo, who specialises in studying shells at archaeological sites, told AFP.

The discovery's location is particularily significant because "the Kimberley coast of Australia is synonymous with pearling, and has been for the better part of the last century, " says Szabo

The pink-and-gold-coloured pearl is almost completely spherical, and measures five-millimeters in diameter. Because the pearl was nearly perfect round researchers were able to use a micro CT scan to test its age as well as prove that is was naturally occurring rather than a modern cultured pearl.

Pearl producing oysters have been used in rainmaking ceremonies in indigenous cultures, and their shells have been found in the central desert more than 930 miles away. Archaeologists have known about the rainmaking rituals but were not aware of how far back in history they had been practiced until now.

"Studying the pearl has led us to the study of the layer in which it's found," Szabo said.

"In indigenous terms, that's telling a really interesting story about a cultural tradition to do with pearl shells which we knew historically but we've never been able to prove that it went back into the past."

The pearl is set to go on display at the Western Australian Maritime Museum in Perth later this month, with details of the find published in the Australian Archaeology journal.

Kathleen Marino M.A, G.G., AJP, NAJA