Crater of Diamonds State Park is a Arkansas state park in Pike County,

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...

, in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. The park features a 37.5-acre (15.2 ha) plowed field, the world's only

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, b ...

-bearing site accessible to the public. Diamonds have continuously been discovered in the field since 1906, including the Strawn-Wagner Diamond. The site became a state park in 1972 after the

Arkansas Department of Parks and Tourism The Arkansas Department of Parks, Heritage, and Tourism (ADPHT) is an executive department of the government of the U.S. state of Arkansas. It is responsible for promoting, protecting, interpreting, and managing the state's natural and cultural ...

purchased the site from the Arkansas Diamond Company and Ozark Diamond Mines Corporation, who had previously operated the site as a tourist attraction.

History

Diamond mines of Arkansas supplement Nashville News 1906

In August 1906, John Huddleston found two strange crystals on the surface of his farm near

Murfreesboro, Arkansas Murfreesboro is a city in, and the county seat of, Pike County, Arkansas, United States. Its population was 1,641 at the 2010 census. The city is known for the Crater of Diamonds State Park located south of the city. History In 1906, diamond ...

. The following month, Huddleston and his wife, Sarah, sold an option on the to a group of

Little Rock ( The "Little Rock") , government_type = Council-manager , leader_title = Mayor , leader_name = Frank Scott Jr. , leader_party = D , leader_title2 = Council , leader_name2 ...

investors headed by banker-attorney Samuel F. (Sam) Reyburn, who undertook a careful, deliberate test of the property. After 1906, several attempts at commercial diamond

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...

failed. The only significant yields came from the original surface layer, where erosion over a long period of time had concentrated diamonds. In the early period, 1907–1932, yields from this "black gumbo" surface material often exceeded thirty carats per hundred loads (50 mg/Mg) (standard 1600-pound tramload of the early period). Highest yields from the undisturbed subsurface material (described as

kimberlite Kimberlite is an igneous rock and a rare variant of peridotite. It is most commonly known to be the main host matrix for diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an diamond called the Star of S ...

volcanic breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of d ...

by the U.S. Geological Survey) were two carats per hundred loads (3.5 mg/Mg) in 1908 and about two carats per hundred

short ton The short ton (symbol tn) is a measurement unit equal to . It is commonly used in the United States, where it is known simply as a ton, although the term is ambiguous, the single word being variously used for short, long, and metric ton. The var ...

s (4.4 mg/Mg) in 1943−1944. Because equipment of the early period usually included bottom screens with mesh larger than 1/16 inch (1.6 mm), thousands of smaller diamonds were allowed to pass through. The bulk of these ended up in drainage cuts of varying depths all over the field and in the big natural drains on the east and west edges of the diamond-bearing section of the volcanic deposit (approximately of volcanic breccia on the east side of the pipe). In recent decades, those small diamonds have been fruitful for recreational diamond diggers. Soon after the first diamond was found, a " diamond rush" created a

boomtown A boomtown is a community that undergoes sudden and rapid population and economic growth, or that is started from scratch. The growth is normally attributed to the nearby discovery of a precious resource such as gold, silver, or oil, althou ...

atmosphere around Murfreesboro. According to old tales, hotels in Murfreesboro turned away 10,000 people in the space of a year. Supposedly, these aspiring diamond miners formed a

tent city A tent city is a temporary housing facility made using tents or other temporary structures. State governments or military organizations set up tent cities to house evacuees, refugees, or soldiers. UNICEF's Supply Division supplies expandable te ...

near the mine, which was named "Kimberly" in honor of the famous Kimberley diamond district in South Africa. On the other hand, all available evidence indicates that the Town of Kimberly originated as a land-development venture in 1909, initiated by Mallard M. Mauney and his oldest son, Walter, on their land immediately south of Murfreesboro. The project failed soon afterward as the speculative boom generated by the diamond discovery collapsed. Today, the Kimberly area is almost all cow pasture, owned by Mauney's descendants. During WWII the U.S. government took control of the mine and granted a contract to Glen Martin to extract this rare war materiel. Although diamonds were obtained, and the concentration of diamonds similar to other producing mines, this was not fully successful as a venture due to the large costs involved with U.S. labor. After the war, the property was returned to the previous owners. From 1951 to 1972, the crater hosted several private tourist attractions. The first, The Diamond Preserve of the United States, lasted about one year. In late 1951, Howard A. Millar stepped in and salvaged the infant tourist industry. In April 1952, Millar and his wife, Modean, launched the Crater of Diamonds attraction. Howard Millar, an accomplished writer and promoter, stirred unprecedented national publicity and drew enough visitors to sustain the operation. In March 1956, a visitor found the Star of Arkansas on the cleared surface. The rare beauty weighed . Later, Roscoe Johnston opened a rival tourist attraction, the Arkansas Diamond Mine, on the main part of the diamond field. The rivalry between the two tourist operations left both in a weakened position. In 1970, the entire volcanic formation was consolidated by a private partnership, which then reassigned the property to General Earth Minerals (GEM) of Dallas, Texas. GEM expected to turn the property over for a profit, but ended up heavily indebted to GF Industries (GFI) of Dallas. Upon default, GFI took the property in July 1971. GEM consolidated the tourist operation as well as the property. GFI continued the attraction until it sold the volcanic formation and some to the

State of Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

in March 1972 for $750,000. The tourist operation continued as the centerpiece of Crater of Diamonds State Park. Due in part to the park, and also because Arkansas was the first place outside South Africa where diamonds were found at their original volcanic source, this special gem has come to be associated with the Natural State. A large diamond symbol has dominated the state flag since 1912. The Arkansas State Quarter, released in 2003, bears a diamond on its face, as do the current license plates.

Geology

The Crater of Diamonds

volcanic pipe Volcanic pipes or volcanic conduits are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. They are considered to be a type of ''diatreme''. Volcanic pipes are composed of a deep, narrow cone o ...

is part of a 95-million-year-old eroded

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...

. The deeply sourced

lamproite Lamproite is an ultrapotassic mantle-derived volcanic or subvolcanic rock. It has low CaO, Al2O3, Na2O, high K2O/Al2O3, a relatively high MgO content and extreme enrichment in incompatible elements. Lamproites are geographically widespread ...

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...

, from the upper mantle, brought the diamonds to the surface. The diamonds had crystallized in the

craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and ...

ic root of the continent long before and were sampled by the magma as it rose to the surface. The geology of the area and the diamond formation process itself were the subjects of the Ph.D. dissertation of Roland Everett Langford in 1973 of the University of Georgia. In it, he proposed a gas phase reaction from the reduction of carbon monoxide and carbon dioxide in the upper mantle. The dissertation was on display at the state park for many years. More recent research by geologist Dennis Dunn (Ph.D. dissertation 2002) established that the diamondiferous epiclastic rocks range from olivine lamproite to phlogopite and olivine-rich tuffs. Mantle xenolith chemistry were used to derive maximum pressures of ~5 GPa and temperatures of 1000 °C for the upper mantle origin of the lamproitic magma. The lamproite diamond source is unusual, as almost all diamonds are mined from

and from alluvial deposits of diamonds weathered from kimberlite. The most prominent lamproite diamond source is the Argyle diamond mine in Australia.

Recreation

Crater of Diamonds State Park is known for the 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. 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. The park offers campers 47 Class AAA facilities near the Little Missouri River.

Diamond mine

Crater of Diamonds State Park is situated over an eroded

. The park is open to the public and, for a small fee,

rockhound Amateur geology or rock collecting (also referred to as rockhounding in the United States and Canada) is the non-professional study and hobby of collecting rocks and minerals or fossil specimens from the natural environment.Sinkankas, John. Minera ...

s and visitors can dig for diamonds and other

gemstone A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...

s. Park visitors find more than 600 diamonds each year of all colors and grades. Over 29,000 diamonds have been found in the crater since it became a state park. Visitors may keep any gemstone they find regardless of its value. In addition to diamonds, visitors may find semi-precious gems such as

amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος ''amethystos'' from α- ''a-'', "not" and μεθύσκω (Ancient Greek) / μεθώ (Modern Greek), "intoxicate", a reference to the belief that ...

agate Agate () is a common rock formation, consisting of chalcedony and quartz as its primary components, with a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in Anci ...

, and

jasper Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases,Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213PDF/ref ...

or approximately 40 other minerals such as

garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different ...

, phlogopite,

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

baryte Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

, and

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

Notable diamonds found

References

External links

*
Official State Park Timeline

State Park latest diamond finds

History of the Crater. The Pike County Archives and History Society
Rockhounding Arkansas page on the Craterarchive

( ttps://web.archive.org/web/20211002051553/http://arkansasroadstories.com/crater.html archive
Encyclopedia of Arkansas: Diamond Mining
{{DEFAULTSORT:Crater Of Diamonds State Park State parks of Arkansas Diamond mines in the United States Natural history of Arkansas Parks on the National Register of Historic Places in Arkansas Diatremes of the United States Volcanoes of Arkansas Cretaceous volcanoes Geology museums in Arkansas Museums in Pike County, Arkansas Protected areas established in 1972 Protected areas of Pike County, Arkansas Landforms of Pike County, Arkansas National Register of Historic Places in Pike County, Arkansas Mining in Arkansas