A diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut. Cut does not refer to shape, but the symmetry and polish of a diamond; the cut of a diamond affects a diamond's brilliance. In order to best use a diamond gemstone's material properties, a number of different diamond cuts have been developed. A diamond cut constitutes a more or less symmetrical arrangement of facets, which together modify the shape and appearance of a diamond crystal. Diamond cutters must consider several factors, such as the shape and size of the crystal, when choosing a cut; the practical history of diamond cuts can be traced back to the Middle Ages, while their theoretical basis was not developed until the turn of the 20th century. Design creation and innovation continue to the present day: new technology—notably laser cutting and computer-aided design—has enabled the development of cuts whose complexity, optical performance, waste reduction were hitherto unthinkable.
The most popular of diamond cuts is the modern round brilliant, whose facet arrangements and proportions have been perfected by both mathematical and empirical analysis. Popular are the fancy cuts, which come in a variety of shapes, many of which were derived from the round brilliant. A diamond's cut is evaluated by trained graders, with higher grades given to stones whose symmetry and proportions most match the particular "ideal" used as a benchmark; the strictest standards are applied to the round brilliant. Different countries base their cut grading on different ideals: one may speak of the American Standard or the Scandinavian Standard, to give but two examples; the history of diamond cuts can be traced to the late Middle Ages, before which time diamonds were employed in their natural octahedral state—anhedral diamonds were not used in jewelry. The first "improvements" on nature's design involved a simple polishing of the octahedral crystal faces to create and unblemished facets, or to fashion the desired octahedral shape out of an otherwise unappealing piece of rough.
This was called the point cut and dates from the mid 14th century. By the mid 15th century, the point cut began to be improved upon: a little less than one half of the octahedron would be sawn off, creating the table cut; the importance of a culet was realised, some table-cut stones may possess one. The addition of four corner facets created the old single cut. Neither of these early cuts would reveal. At the time, diamond was valued chiefly for its adamantine superlative hardness. For this reason, colored gemstones such as ruby and sapphire were far more popular in jewelry of the era. In or around 1476, Lodewyk van Berquem, a Flemish polisher of Bruges, introduced the technique of absolute symmetry in the disposition of facets using a device of his own invention, the scaif, he cut stones in the shape known as briolette. About the middle of the 16th century, the rose or rosette was introduced in Antwerp: it consisted of triangular facets arranged in a symmetrical radiating pattern, but with the bottom of the stone left flat—essentially a crown without a pavilion.
Many large, famous Indian diamonds of old feature a rose-like cut. However, Indian "rose cuts" were far less symmetrical as their cutters had the primary interest of conserving carat weight, due to the divine status of diamond in India. In either event, the rose cut continued to evolve, with its depth and arrangements of facets being tweaked; the first brilliant cuts were introduced in the middle of the 17th century. Known as Mazarins, they had 17 facets on the crown, they are called double-cut brilliants as they are seen as a step up from old single cuts. Vincent Peruzzi, a Venetian polisher increased the number of crown facets from 17 to 33, thereby increasing the fire and brilliance of the cut gem, properties that in the Mazarin were incomparably better than in the rose, yet Peruzzi-cut diamonds, when seen nowadays, seem exceedingly dull compared to modern-cut brilliants. Because the practice of bruting had not yet been developed, these early brilliants were all rounded squares or rectangles in cross-section.
Given the general name of cushion—what are known today as old mine cuts—these were common by the early 18th century. Sometime the old European cut was developed, which had a shallower pavilion, more rounded shape, different arrangement of facets; the old European cut was the forerunner of modern brilliants and was the most advanced in use during the 19th century. Around 1900, the development of diamond saws and good jewelry lathes enabled the development of modern diamond cutting and diamond cuts, chief among them the round brilliant cut. In 1919, Marcel Tolkowsky analyzed this cut: his calculations took both brilliance and fire into consideration, creating a delicate balance between the two. Tolkowsky's calculations would serve as the basis for all future brilliant cut modifications and standards. Tolkowsky's model of the "ideal" cut is not perfect; the original mo
Arkansas is a state in the southern region of the United States, home to over 3 million people as of 2018. Its name is of Siouan derivation from the language of the Osage denoting their related kin, the Quapaw Indians; the state's diverse geography ranges from the mountainous regions of the Ozark and the Ouachita Mountains, which make up the U. S. Interior Highlands, to the densely forested land in the south known as the Arkansas Timberlands, to the eastern lowlands along the Mississippi River and the Arkansas Delta. Arkansas is the 33rd most populous of the 50 United States; the capital and most populous city is Little Rock, located in the central portion of the state, a hub for transportation, business and government. The northwestern corner of the state, such as the Fayetteville–Springdale–Rogers Metropolitan Area and Fort Smith metropolitan area, is a population and economic center; the largest city in the state's eastern part is Jonesboro. The largest city in the state's southeastern part is Pine Bluff.
The Territory of Arkansas was admitted to the Union as the 25th state on June 15, 1836. In 1861, Arkansas withdrew from the United States and joined the Confederate States of America during the Civil War. On returning to the Union in 1868, the state continued to suffer due to its earlier reliance on slavery and the plantation economy, causing the state to fall behind economically and socially. White rural interests continued to dominate the state's politics until the civil rights movement. Arkansas began to diversify its economy following World War II and relies on its service industry, poultry, tourism and rice; the culture of Arkansas is observable in museums, novels, television shows and athletic venues across the state. People such as politician and educational advocate William Fulbright; the name Arkansas was applied to the Arkansas River and derives from a French term, the plural term for Quapaws, a Dhegiha Siouan-speaking Native American people who settled in Arkansas around the 13th century.
This comes from an Algonquian term, /akansa/, for the Quapaws, is also the root term for Kansas. The name has been spelled in a variety of fashions. In 1881, the pronunciation of Arkansas with the final "s" being silent was made official by an act of the state legislature after a dispute arose between Arkansas's two U. S. senators as one favored the pronunciation as AR-kən-saw while the other favored ar-KAN-zəs. In 2007, the state legislature passed a non-binding resolution declaring that the possessive form of the state's name is Arkansas's, followed by the state government. Arkansas borders Louisiana to the south, Texas to the southwest, Oklahoma to the west, Missouri to the north, Tennessee and Mississippi to the east; the United States Census Bureau classifies Arkansas as a southern state, sub-categorized among the West South Central States. The Mississippi River forms most of Arkansas's eastern border, except in Clay and Greene, counties where the St. Francis River forms the western boundary of the Missouri Bootheel, in many places where the channel of the Mississippi has meandered from its original 1836 course.
Arkansas can be split into two halves, the highlands in the northwest half and the lowlands of the southeastern half. The highlands are part of the Southern Interior Highlands, including The Ozarks and the Ouachita Mountains; the southern lowlands include the Arkansas Delta. This dual split can yield to general regions named northwest, northeast, southeast, or central Arkansas; these directionally named regions are broad and not defined along county lines. Arkansas has seven distinct natural regions: the Ozark Mountains, Ouachita Mountains, Arkansas River Valley, Gulf Coastal Plain, Crowley's Ridge, the Arkansas Delta, with Central Arkansas sometimes included as a blend of multiple regions; the southeastern part of Arkansas along the Mississippi Alluvial Plain is sometimes called the Arkansas Delta. This region is a flat landscape of rich alluvial soils formed by repeated flooding of the adjacent Mississippi. Farther away from the river, in the southeast portion of the state, the Grand Prairie consists of a more undulating landscape.
Both are fertile agricultural areas. The Delta region is bisected by a geological formation known as Crowley's Ridge. A narrow band of rolling hills, Crowley's Ridge rises from 250 to 500 feet above the surrounding alluvial plain and underlies many of the major towns of eastern Arkansas. Northwest Arkansas is part of the Ozark Plateau including the Ozark Mountains, to the south are the Ouachita Mountains, these regions are divided by the Arkansas River; these mountain ranges are part of the U. S. Interior Highlands region, the only major mountainous region between the Rocky Mountains and the Appalachian Mountains; the highest point in the state is Mount Magazine in the Ouachita Mountains, which rises to 2,753 feet above sea level. Arkansas has many rivers and reservoirs within or along its borders. Major tributaries of the Mississippi River include the Arkansas River, the White River, the St. Francis River; the Arkansas is fed by the Mulberry River and the Fou
Crater of Diamonds State Park
Crater of Diamonds State Park is a 911-acre Arkansas state park in Pike County, Arkansas, in the United States. The park features a 37.5-acre plowed field, the world's only diamond-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 purchased the site from the Arkansas Diamond Company and Ozark Diamond Mines Corporation, who had operated the site as a tourist attraction previously. In August 1906, John Huddleston found two strange crystals on the surface of his 243-acre farm near Murfreesboro and soon became known as the first person outside South Africa to find diamonds at their original source; the following month and his wife, sold an option on the 243 acres to a group of Little Rock investors headed by banker-attorney Samuel F. Reyburn, who undertook a careful, deliberate test of the property. After 1906, several attempts at commercial diamond mining 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 exceeded thirty carats per hundred loads. Highest yields from the undisturbed subsurface material were two carats per hundred loads in 1908 and about two carats per hundred short tons in 1943−1944; because equipment of the early period included bottom screens with mesh larger than 1/16 inch, 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. In recent decades, those small diamonds have been the bread-and-butter of recreational diamond digging. Soon after the first diamond was found, a "diamond rush" created a boomtown atmosphere around Murfreesboro. According to old tales, hotels in Murfreesboro turned away 10,000 people in the space of a year.
These aspiring diamond miners formed a tent city near the mine, 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 south of Murfreesboro; the project failed soon afterward as the speculative boom generated by the diamond discovery collapsed. Today, the Kimberly area is all cow pasture, owned by Mauney's descendants. During the Second World War, the U. S. government took over the mine and granted a contract to Glen Martin to extract this rare war material. Although diamonds were obtained, the concentration of diamonds similar to other producing mines, this was not 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 only about one year. In late 1951, Howard A. Millar salvaged the infant tourist industry. In April 1952, Millar and his wife, launched their 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 15.33 carats. 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 reassigned the property to General Earth Minerals of Dallas, Texas. GEM expected to turn the property over for a profit, but ended up indebted to GF Industries 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 80-acre volcanic formation and some 800 acres to the State of Arkansas 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, 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. The Crater of Diamonds volcanic pipe is part of a 95-million-year-old eroded volcano; the sourced lamproite magma, from the upper mantle, brought the diamonds to the surface. The diamonds had crystallized in the cratonic 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 from the University of Georgia.
The dissertation was on display at the state park for many years. The lamproite diamond sour
Texas is the second largest state in the United States by both area and population. Geographically located in the South Central region of the country, Texas shares borders with the U. S. states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the southwest, while the Gulf of Mexico is to the southeast. Houston is the most populous city in Texas and the fourth largest in the U. S. while San Antonio is the second-most populous in the state and seventh largest in the U. S. Dallas–Fort Worth and Greater Houston are the fourth and fifth largest metropolitan statistical areas in the country, respectively. Other major cities include Austin, the second-most populous state capital in the U. S. and El Paso. Texas is nicknamed "The Lone Star State" to signify its former status as an independent republic, as a reminder of the state's struggle for independence from Mexico; the "Lone Star" can be found on the Texan state seal.
The origin of Texas's name is from the word taysha. Due to its size and geologic features such as the Balcones Fault, Texas contains diverse landscapes common to both the U. S. Southern and Southwestern regions. Although Texas is popularly associated with the U. S. southwestern deserts, less than 10% of Texas's land area is desert. Most of the population centers are in areas of former prairies, grasslands and the coastline. Traveling from east to west, one can observe terrain that ranges from coastal swamps and piney woods, to rolling plains and rugged hills, the desert and mountains of the Big Bend; the term "six flags over Texas" refers to several nations. Spain was the first European country to claim the area of Texas. France held a short-lived colony. Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845, Texas joined the union as the 28th state; the state's annexation set off a chain of events that led to the Mexican–American War in 1846.
A slave state before the American Civil War, Texas declared its secession from the U. S. in early 1861, joined the Confederate States of America on March 2nd of the same year. After the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation. Four major industries shaped the Texas economy prior to World War II: cattle and bison, cotton and oil. Before and after the U. S. Civil War the cattle industry, which Texas came to dominate, was a major economic driver for the state, thus creating the traditional image of the Texas cowboy. In the 19th century cotton and lumber grew to be major industries as the cattle industry became less lucrative, it was though, the discovery of major petroleum deposits that initiated an economic boom which became the driving force behind the economy for much of the 20th century. With strong investments in universities, Texas developed a diversified economy and high tech industry in the mid-20th century.
As of 2015, it is second on the list of the most Fortune 500 companies with 54. With a growing base of industry, the state leads in many industries, including agriculture, energy and electronics, biomedical sciences. Texas has led the U. S. in state export revenue since 2002, has the second-highest gross state product. If Texas were a sovereign state, it would be the 10th largest economy in the world; the name Texas, based on the Caddo word táyshaʼ "friend", was applied, in the spelling Tejas or Texas, by the Spanish to the Caddo themselves the Hasinai Confederacy, the final -s representing the Spanish plural. The Mission San Francisco de los Tejas was completed near the Hasinai village of Nabedaches in May 1690, in what is now Houston County, East Texas. During Spanish colonial rule, in the 18th century, the area was known as Nuevo Reino de Filipinas "New Kingdom of the Philippines", or as provincia de los Tejas "province of the Tejas" also provincia de Texas, "province of Texas", it was incorporated as provincia de Texas into the Mexican Empire in 1821, declared a republic in 1836.
The Royal Spanish Academy recognizes both spellings and Texas, as Spanish-language forms of the name of the U. S. State of Texas; the English pronunciation with /ks/ is unetymological, based in the value of the letter x in historical Spanish orthography. Alternative etymologies of the name advanced in the late 19th century connected the Spanish teja "rooftile", the plural tejas being used to designate indigenous Pueblo settlements. A 1760s map by Jacques-Nicolas Bellin shows a village named Teijas on Trinity River, close to the site of modern Crockett. Texas is the second-largest U. S. state, with an area of 268,820 square miles. Though 10% larger than France and twice as large as Germany or Japan, it ranks only 27th worldwide amongst country subdivisions by size. If it were an independent country, Texas would be the 40th largest behind Zambia. Texas is in the south central part of the United States of America. Three of its borders are defined by rivers; the Rio Grande forms a natural border with the Mexican states of Chihuahua, Nuevo León, Tamaulipas to the south.
The Red River forms a natural border with Arkansas to the north. The Sabine River forms a natural border with Louisiana to the east; the Texas Panhandle has an eastern border with Oklahoma at 100° W, a northern border with Oklahoma at 36°30' N and a western
Amarillo is the 14th-most populous city in the state of Texas, United States. It is the largest city in the Texas Panhandle, the seat of Potter County. A portion of the city extends into Randall County; the estimated population was 199,826 as of 2017. The Amarillo metropolitan area has an estimated population of 276,020 in four counties as of 2017; the metro population is projected to surpass 310,000 in 2020. Amarillo named Oneida, is situated in the Llano Estacado region; the availability of the railroad and freight service provided by the Fort Worth and Denver City Railroad contributed to the city's growth as a cattle-marketing center in the late 19th century. The city was once the self-proclaimed "Helium Capital of the World" for having one of the country's most productive helium fields; the city is known as "The Yellow Rose of Texas", most "Rotor City, USA" for its V-22 Osprey hybrid aircraft assembly plant, as well as "Bomb City". Amarillo operates one of the largest meat-packing areas in the United States.
Pantex, the only nuclear weapons assembly and disassembly facility in the country, is a major employer. The location of this facility gave rise to the nickname Bomb City; the attractions Cadillac Ranch and Big Texan Steak Ranch are located adjacent to Interstate 40. U. S. Highway 66 passed through the city. Large ranches exist in the Amarillo area: among others, the defunct XIT Ranch and the still functioning JA Ranch founded in 1877 by Charles Goodnight and John George Adair. Goodnight continued the partnership for a time after Adair's death with Adair's widow, Cornelia Wadsworth Ritchie Adair, the sole owner from 1887 until her death in 1921. During April 1887, J. I. Berry established a site for a town after he chose a well-watered section along the way of the Fort Worth and Denver City Railroad, which had begun building across the Texas Panhandle. Berry and Colorado City, merchants wanted to make their new town site the region's main trading center. On August 30, 1887, Berry's town site won the county seat election and was established in Potter County.
Availability of the railroad and freight service after the county seat election made the town a fast-growing cattle-marketing center. The settlement was called Oneida. Early residents pronounced the city's name more similar to the Spanish pronunciation ah-mə-REE-yoh, displaced by the current pronunciation. On June 19, 1888, Henry B. Sanborn, given credit as the "Father of Amarillo", his business partner Joseph F. Glidden began buying land to the east to move Amarillo after arguing that Berry's site was on low ground and would flood during rainstorms. Sanborn offered to trade lots in the new location to businesses in the original city's site and help with the expense of moving to new buildings, his incentives won over people, who moved their businesses to Polk Street in the new commercial district. Heavy rains flooded Berry's part of the town in 1889, prompting more people to move to Sanborn's location; this led to another county seat election making Sanborn's town the new county seat in 1893. By the late 1890s, Amarillo had emerged as one of the world's busiest cattle-shipping points, its population grew significantly.
The city became a grain elevator and feed-manufacturing center after an increase in production of wheat and small grains during the early 1900s. Discovery of natural gas in 1918 and oil three years brought oil and gas companies to the Amarillo area; the United States government bought the Cliffside Gas Field with high helium content in 1927 and the Federal Bureau of Mines began operating the Amarillo Helium plant two years later. The plant was the sole producer of commercial helium in the world for a number of years; the U. S. National Helium Reserve is stored in the Bush Dome Reservoir at the Cliffside facility. Following the lead of the Fort Worth and Denver City Railroad, the Atchison and Santa Fe Railway and Chicago, Rock Island and Pacific Railroad established services to and from Amarillo; each of these three carriers maintained substantial freight and passenger depots and repair facilities in the city through most of the 20th century and were major employers within the community. In 1929, Ernest O. Thompson, a decorated World War I general and a major businessman in Amarillo, was elected mayor to succeed Lee Bivins.
Thompson worked to reduce utility rates. He joined the Texas Railroad Commission by appointment in 1933 and was elected to full terms in 1934, 1940, 1946, 1952, 1958, he became an international expert on conservation. The first Mrs. Thompson, May Peterson Thompson, a former Metropolitan Opera singer, was involved in the arts while in Amarillo and when the couple lived in Austin. Amarillo entered an economic depression. U. S. Routes 60, 87, 287, 66 intersected at Amarillo, making it a major tourist stop with numerous motels and curio shops. World War II led the establishment of Amarillo Army Air Field in east Amarillo and the nearby Pantex Army Ordnance Plant, which produced bombs and ammunition. After the end of the war, both of the facilities were closed; the Pantex Plant produced nuclear weapons throughout the Cold War. In 1949, a deadly F4 tornado devastated much of Amaril