Crater of Diamonds State Park

Template:Short description Template:Use American English Template:Use mdy dates Template:Infobox protected area Crater of Diamonds State Park is a Template:Convert Arkansas state park in Pike County, Arkansas, in the United States. The park has a Template:Convert plowed field which is one of the few diamond-bearing sites accessible to the public. Diamonds have been discovered in the field continuously since 1906, including the graded-perfect Strawn-Wagner Diamond, found in 1990, and the Uncle Sam, found in 1924, which at over 40 carats is the largest diamond ever found in the United States.

The site became a state park in 1972 when the Arkansas Department of Parks and Tourism purchased the site from private owners in Dallas, Texas, which had operated the site as a tourist attraction.<ref name="enc" />

History

In 1889, Arkansas state geologist John Branner investigated the site of an 1842 report noting an igneous intrusion amidst sedimentary rock near Murfreesboro. He determined it was a kimberlite, but without the associated diamonds. In early 1906 John Wesley Huddleston purchased the area, looking for gold. Instead, in August, he found two diamonds, 3- and 4.5-carats, as identified by George Frederick Kunz. Visiting the site with Henry Stephens Washington, Kunz noted of the 140 diamonds collected from the surface, "They are absolutely perfect and are equal to the finest stones [of Africa] or that were ever found in India...[E]conomical extraction [should be entirely] successful." The Arkansas Diamond Company was formed, headed by the Little Rock banker Samuel Reyburn, and Huddleston sold out for $36,000. Kunz and Washington prepared a mining plan for the 73 acre orebody, and initially 1400 diamonds were found in the regolith. Soon ten thousand prospectors started search the outlying area for diamonds, and for fifty cents a day, they could keep any diamonds found on the neighboring Mauney's property. The Mauneys also sold lots for the town of Kimberly, which soon contained stores, restaurants, and a hotel. In 1908, the Arkansas Diamond Company hired John Fuller, a former De Beers engineer. Yet money was wasted, and the thousands of diamonds mined were mainly less than half a carat, and the few large ones were industrial grade. In 1912, the mine closed, after running out of Financial capital. Only a watchman and assistants continued looking for diamonds<ref name=kk>Template:Cite book</ref>

In 1912, Austin Q. Millar and his son Howard Millar, rented and bought surrounding Murfreesboro properties, including the Mauney place, and established an ore processing system. For the next seven years, they mined thousands of modest stones. On 13 January 1919, the operation ended after arson burned the entire operation.<ref name=kk/>

In 1919, the Arkansas Diamond Company reorganized, and hire Stanley Zimmerman, another engineer. However, he condemned the mine, and the company failed a second time. The 3000 gem-quality diamonds that had been stockpiled were acquired by mortgage holder J.P. Morgan & Co. vice president Tom Cochran. The collection included the 40.23 carat Uncle Sam.<ref name=kk/>

In the 1920s, the Arkansas Diamond Company was able to restart with a small operation in which some diamonds were recovered before operations ended in 1932.<ref name=kk/>

In 1941, Charles Wilkinson bought the property. During WWII, Wilkinson sent Arkansas Governor Homer Martin Adkins, Senator Hattie Caraway, and the head of Schenck & Van Haelen jewelers, to convince President Franklin Roosevelt to reopen the pipe, since the country was in need of industrial diamonds. The United States Bureau of Mines excavated 435 tons from the first 50 feet, but by 1944, had found only 32 diamonds, averaging a quarter-carat each. With the war over, the mine closed.<ref name=kk/>Template:Rp

In 1951 The Diamond Preserve opened as a diamond mining attraction, followed the next year by Millar's Crater of Diamonds. In 1956, Winifred Parker found the 15.36-carat white Star of Arkansas. In 1957, Ruth McRae found the 3.11-carat white Eisenhower Diamond. In 1969, Millar sold his property to General Earth Minerals. In 1971, the Arkansas State Parks, Recreation, and Travel Commission voted to acquire the property for a state park. <ref>Template:Cite web</ref>

Geology

The Early Cretaceous Prairie Creek Diatreme outcrops include magmatic lamproite, pyroclastic lamproite where diamonds are recovered, and maar epiclastics. According to Howard and Hanson, "Lamproites form from partially melted mantle at depths exceeding 93 miles. The rising material is forced to the surface in volcanic pipes, bringing with it xenoliths and xenocryst diamonds from the harzburgitic peridotite or eclogite mantle regions where diamond formation is stabilized. In the instance of the Arkansas lamproites, the diamonds are of eclogite host origin."<ref>Template:Cite web</ref>

In 2002, research by geologist Dennis Dunn (Ph.D. dissertation 2002) found that the diamondiferous epiclastic rocks range from olivine lamproite to phlogopite and olivine-rich tuffs. The chemistry of the mantle xenolith was used to derive maximum pressures of around 5 GPa and temperatures of 1000 °C for the upper mantle origin of the lamproitic magma.<ref>Template:Cite web</ref>

Recreation

Crater of Diamonds State Park is known for the Template:Convert plowed field on which visitors can hunt for diamonds and other semi-precious gems. On average, two diamonds are found per day by park visitors.<ref name=PDF/> A visitor center contains information about the geology of the park, a gift shop, and a cafe. Interested visitors can continue to the Diamond Discovery Center, which offers an interpretive look at prospecting for diamonds. The Diamond Springs aquatic playground, enclosed pavilion, trails, and picnic areas surround the diamond field.<ref name="guide">Template:Cite book</ref> The park offers campers facilities near the Little Missouri River.<ref name=PDF>Template:Cite web</ref>

Diamond mine

Crater of Diamonds State Park is situated over an eroded lamproite volcanic pipe. The park is open to the public and, for a small fee, rockhounds and visitors can dig for diamonds and other gemstones. Park visitors find more than 600 diamonds each year of all colors and grades.<ref name=Media>Template:Cite web</ref><ref name="edwardsDAILYRECORD5aug2019" /> As of 2015, over 75,000 diamonds had been found in the crater.<ref name="edwardsDAILYRECORD5aug2019" /> Visitors may keep any gemstone they find regardless of its value.<ref name=Media/>

In addition to diamonds, visitors may find semi-precious gems such as amethyst, agate, and jasper or approximately 40 other minerals such as garnet, phlogopite, quartz, baryte, and calcite.

Notable diamonds found

Year	Diamond Name	Weight (carat)	Weight (gram)	Color	Finder
1917	Canary	Template:Convert	canary yellow	Template:Sortname of the Arkansas Diamond Company	Donated in 1926 to the National Museum of Natural History by the heirs of Washington Roebling<ref name=":2" /><ref>Template:Cite web</ref><ref>Template:Cite web</ref>
1924	Uncle Sam	Template:Convert		Template:Sortname	Largest diamond ever discovered in the United States; as of 2022 in the collection of the Smithsonian<ref name=":1">Template:Cite web</ref><ref name="edwardsDAILYRECORD5aug2019">Template:Cite web</ref><ref name=":2">Template:Cite web</ref>
1956	Star of Arkansas	Template:Convert		Winifred Parker<ref>Template:Cite web</ref>
1964	Star of Murfreesboro	Template:Convert		Template:Sortname	Largest diamond ever found by a tourist in the Arkansas area; it was valued at $15,000 in 1964.<ref name="edwardsDAILYRECORD5aug2019" />
1975	Amarillo Starlight	Template:Convert		Template:Sortname	Cut into a Template:Convert marquise.<ref name=":1" /><ref name="edwardsDAILYRECORD5aug2019" />
1977	Kahn Canary	Template:Convert	canary yellow	Template:Sortname	Uncut and naturally flawless. Set by Dunay into a ring for Hillary Clinton for a 1993 inaugural ball<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
1981	Star of Shreveport	Template:Convert		Template:Sortname
1990	Strawn-Wagner Diamond	Template:Convert	white	Template:Sortname	Found by a local resident, graded perfect.<ref>Template:Cite magazine</ref> In the collection of the park.<ref>Template:Cite web</ref>
2015	Esperanza Diamond	Template:Convert	Type IIa, D IF	Template:Sortname	Flawless or near flawless. Cut and polished in Arkansas by Mike Botha<ref>Template:Cite web</ref><ref>Template:Cite web</ref><ref>Template:Cite web</ref> After cutting and polishing it was to be set by Erica Courtney then auctioned by Heritage Auctions.<ref>Template:Cite web</ref>
2024	Carine Diamond	Template:Convert	Chocolate	Template:Sortname	Chocolate-colored. Eighth-largest diamond found in the United States. Found by Julien Navas for a wedding ring for his fiancée Carine Eizlini<ref>Template:Cite news</ref><ref>Template:Cite web</ref><ref>Template:Cite web</ref>