document_title: Friday Night Lights (film)

question_text: who wins the game in friday night lights

text: Friday Night Lights (film)

text: Plot[edit]

text: Bissinger followed the team for the entire 1988 season. However, the book also dealt with—or alluded to—a number of secondary political and social issues existing in Odessa, all of which shared ties to the Permian Panthers football team. These included socioeconomic disparity; racism; segregation (and desegregation); and poverty.

text: The coach, Gary Gaines (Billy Bob Thornton), was constantly in the hot seat. Tied to the successes and failure of the coach and the team in general were the conflicts the players struggled with on and off the gridiron. The coach overused his star player, running back James "Boobie" Miles (Derek Luke), who was seriously injured (he tore his ACL, missed the playoffs, and had a limp for the rest of his life). When this happened, sports radio shows were flooded with calls for Gaines' resignation. Miles' once-arrogant attitude vanished as he saw his once-promising chance of playing big-time college football disappear, and he questioned his future after he noticed his not-so-promising academic standing. While recuperating on his uncle's veranda he observed the garbage collectors doing their rounds, got a glimpse of a different future, and burst into tears.

text: One of the themes of the movie depicted the coach as a father-type figure for the players. For example:

text:
Quarterback Mike Winchell (Lucas Black) struggled with being able to play consistently.
Fullback Don Billingsley (Garrett Hedlund) had a rocky relationship with his alcoholic and abusive father (Tim McGraw). Billingsley silently endured the abuse from his father, who won a state championship at Permian only to find himself unable to get into college and stuck working a dead-end job.
Third-string running back Chris Comer (Lee Thompson Young), who replaced the injured Miles, attempted to get rid of his fear of being hit and getting injured, made worse by seeing his predecessor's season-ending injury. Comer's obsession with fame and recognition also came at a high price that he was at first not ready to pay.
Safety Brian Chavez (Jay Hernandez) was easily the smartest player on the team and the most confident in his future after high school football. He ended up being accepted into Harvard College and Texas Tech Law School.

text: Coach Gaines triumphed and struggled with winning football games and connecting with his players numerous times during their tumultuous season. His job depended on the Panthers' making the playoffs, and his team was in a three-way tie with two other teams at the end of the regular season. Under Texas rules for ties, the tiebreaker was a coin-toss. Permian got a spot. Meanwhile, after Don Billingsley's father drunkenly threw away his championship ring, he broke down and confessed that his failures in life caused him to push his son harshly, pointing out that he wanted his son to at least have one big moment of triumph before dealing with the real world. The team made it to the finals, where they narrowly lost to powerhouse Dallas Carter High School. The movie ended with the coach removing the departing seniors from the depth chart on his wall. Notably, the depth chart has "Case" at quarterback. This referred to Permian's real-life backup quarterback in 1988, Stoney Case, who led Permian, along with Chris Comer, to the 5A state title the following year, and still later made it to the NFL.

text: Cast[edit]

text:
Billy Bob Thornton as Coach Gary Gaines
Lucas Black as Mike Winchell
Garrett Hedlund as Don Billingsley
Derek Luke as James "Boobie" Miles
Jay Hernandez as Brian Chavez
Lee Jackson III as Ivory Christian
Lee Thompson Young as Chris Comer
Tim McGraw as Charles Billingsley
Grover Coulson as L.V. Miles
Connie Britton as Sharon Gaines
Julius Tennon as Coach Freddie James
Connie Cooper as Ms. Winchell
Amber Heard as Maria
Kasey Stevens as Flippy
Rutherford Cravens as Kansas Weslyan Recruiter
Stephen Bishop as Loie Harris
Katherine Willis as Booster Wife
Christian Kane as Brian
Brad Leland as John Aubrey

text: Championship game officials: Tim Crowley, Gary Vaught, Lee Mack Turner

text: Differences between the movie and events[edit]

text: Players[edit]

text:
In the movie, Boobie Miles was depicted as one of the team's three captains, but that honor was held by Ivory Christian, Mike Winchell and Brian Chavez in real life.
In the movie, some of the players' numbers and positions were changed: Boobie Miles was #45 and played tailback in the movie, but in the book he was playing fullback (while Don Billingsley was the tailback) and #35. In the movie, Brian Chavez was the #4 strong safety, while he was the #85 tight end in the book, and Ivory Christian was a defensive end and wore #90, while he was the #62 middle ("Mike") linebacker in the book. At the beginning of the film, as the camera panned over Coach Gaines' depth chart, 'Miles' name was listed under the FB tag. Chris Comer was also the backup fullback in the book, not a third-string tailback. One of the athletic directors in the stadium booth said, "I think he's a sophomore", when Comer was a junior at the time. Comer also wore #45 in the real season, but in the movie he wore #42. Alan Wyles was depicted as a wide receiver when he was the placekicker.
Don Billingsley's father Charlie was depicted in the movie as having won a state championship. In reality, as a junior, the 1968 Permian team lost in the finals.

text: The regular season[edit]

text: In the movie, the team was depicted as practicing in full pads and with full contact on the first day of practice. Under rules of the University Interscholastic League (UIL), the governing body for Texas public school sports, teams cannot use pads or hit until the 4th day of practice (however, in the deleted scenes included in the DVD, a non-pad practice was shown).

text:
A Permian booster was heard toasting Coach Gaines' second season as Permian's head coach. It was his third.
Boobie Miles, in the book, injured his leg by getting his foot caught on the Astroturf during a pre-season scrimmage against Amarillo Palo Duro at Jones Stadium in Lubbock. In the movie, he was tackled by two players at the knee during a blowout non-district game at Ratliff Stadium.
In the movie, the top-ranked Permian Panthers defeated the hapless Marshall Bulldogs in a non-district game. In real life, the third-ranked Marshall Mavericks (whose colors are red and white, not purple and gold) defeated fourth-ranked Permian 13-12. In the movie, the game was the season opener and played on a Friday night in Odessa. In real life, it was Permian's second game of the season, and played at Maverick Stadium in Marshall on a Saturday afternoon. Permian's football team chartered a jet for the 500+ mile trip from Odessa to Marshall, spawning controversy on the cost of the trip. Played before a crowd of more than 12,000 fans at Maverick Stadium, the game was on a searing September afternoon where the temperature topped 100 degrees Fahrenheit (38 °C). The footage shown in the movie was from a game against the Midland High Bulldogs, who weren't mentioned in the movie. Permian defeated the Dawgs 42-0 in district play, but the two teams ended up in a three-way tie along with Midland Lee for the district title.
In the movie, district play began in week 2. In the real regular season, district play began in week 4.
In the movie, Permian defeated "North Shore Galena" in a mid-season (presumably district) game. In reality, North Shore High School was within the Galena Park Independent School District located in the Houston suburbs over 500 miles (800 km) southeast of Odessa. Although North Shore and Permian have both been 5A football powerhouses, they have never played. Furthermore, North Shore did not start seeing football success until the mid 1990s.
In reality, the three teams tied for best district record were Permian, Midland Lee, and Midland High, all with 5-1 district records. In the movie, Permian and Lee were joined not by Midland but by Abilene Cooper, and each team had two district losses. The tie breaking coin flip was held at a truck stop outside of Midland, and Midland High lost (Cooper in the movie), so Permian and Lee went on. Midland High's missing the playoffs was poignant as it had not been to the playoffs since 1951 and did not get back to post-season play until 2002.
A Permian player was shown with coach Gaines at the coin toss. In reality, no players from any of the three schools were allowed at the coin toss. All of Permian's players were on the team bus returning from the game that evening at San Angelo Central. Permian assistant coach Mike Belew drove with Gaines from San Angelo to the site of the coin toss.
In a few scenes, players were shown wearing Under Armour apparel and facemask shields, although in 1988, Under Armour and visors hadn't been invented yet. (Under Armour founder Kevin Plank was in high school in 1988.) The book says they wore green visors, which are now outlawed for high school and college teams.
In the movie, the annual duel against Permian's archrival Midland Lee was portrayed as Lee having a handy lead throughout the game with Permian never having a shot at the victory. In real life, Lee had to come from behind with a late-game touchdown to win the game 22-21.

text: The playoffs[edit]

text:
Permian's first opponent in the playoffs was Amarillo Tascosa and not Dallas Jesuit as in the movie. In 1988, Texas Public Schools (such as Permian, Carter, and Tascosa) and private schools (such as Jesuit) competed in separate leagues with separate playoffs. Jesuit was not allowed to join the previously all-public school UIL until 2003, starting football competition in 2004. Dallas Jesuit and Strake Jesuit of Houston were the only private schools who currently play in the UIL, the rest competing in leagues such as TAPPS and the SPC. Also, with the district setup at that time, it would have been impossible for Permian to play a team from the Dallas/Fort Worth Metroplex until the third round for the playoffs. Nowadays, Permian could play Fort Worth-area teams in the first round of the playoffs, but still could not play Jesuit until round 3. Permian played Dallas Jesuit in Odessa during the regular season in 1988, winning 48-2. Jesuit's only points came on a missed-PAT return, which was a rule instituted that year (the defensive conversion was not allowed in high school football under National Federation of State High School Associations rules, but Texas played by NCAA rules). Jesuit's helmet was shown as white and orange with a sort of wildcat's head logo on it, but in real life they are solid gold without a logo.
In the movie, it was said that Carter was the state's top-ranked team, when Carter was never ranked higher than No. 3 in the Associated Press poll.
Carter played "Hays" High School in the playoffs, which was depicted as wearing green and white and nicknamed the Rams. The real Jack C. Hays High School, located 15 minutes south of Austin in Buda, used red, white, and blue as its colors, and their nickname was the Rebels. Hays was a Class 4A school in 1988 and did not become 5A until 2000. Hays was in the movie because the makers filmed crowd shots at Hays High during a Rebels home game against the Austin Westlake Chaparrals, another team depicted as a Permian playoff victim.
Permian was depicted as playing "San Angelo" in the quarterfinal round. There were two high schools in the San Angelo Independent School District; until 1998, San Angelo Central High School, the district's only 5A school had been in the same district as Permian (having since been transferred, for football only, to the district with Lubbock and Amarillo schools), and could only have played Permian in the quarterfinal round (owing to the structure of UIL playoffs) if they had qualified. However, Central finished 5th in the district that year, and as only two teams from each district qualified in 1988, Permian and Central did not play in the 1988 playoffs. Instead, Permian played Arlington Lamar in the quarterfinals.
On the playoff brackets it shows just the word "Baytown". There were two high schools in Baytown in 1988 (there are now three), the team in the playoffs was Baytown Lee.

text: Permian vs. Carter[edit]

text:
Since 1982, the UIL Class 5A (now 6A) football playoffs have had six rounds (though a second, parallel playoff bracket of five rounds was added in 1990, later also expanded to six rounds in 2006), so while Permian played Dallas Carter in the fifth round, it was a semi-final and not a final. In the Texas playoffs, a team from North or Western Texas always plays a team from the Houston area or Southern Texas in the final[2], so the Carter vs Permian final was not possible. The real-life final featured Carter versus Converse Judson (which defeated Permian in the 1995 state championship). The Carter-Permian game was played in front of 10,000 people in a heavy downpour at The University of Texas at Austin's Memorial Stadium, not in front of 55,000 in the Astrodome in Houston. While the game in the movie was a high-scoring affair (34-28), the real score was 14-9 in favor of Carter. In real life, Permian held a 9-7 lead for most of the game and Carter made the dramatic fourth quarter comeback to win. On the last play of the game, Winchell threw the ball incomplete, rather than running it himself close to the goal line.
The meeting between officials from Permian and Carter at the Midland airport occurred the Sunday prior to the game. Not shown in the movie was the Carter officials changing their minds about a home site from Texas Stadium in Irving to the Cotton Bowl within the Dallas city limits. Under UIL rules, if the schools cannot agree to a neutral site, each side picks a "home" site and a "neutral" site, and two coin tosses are conducted. The first was to determine whether a "home" or "neutral" site will be used, and the second to determine which team's site will be used. After a tense battle between the sides, they agreed to play the game at Austin.
In the movie, Gaines suggested at first suggests San Antonio as a potential neutral site, which would have meant playing the game at Alamo Stadium, since the Alamodome did not open until 1993. The other neutral site suggestion in the movie was College Station, presumably meaning Kyle Field at Texas A&M.
The revocation of Carter's state championship following their use of an academically ineligible player was never mentioned, nor was the prolonged legal battle that Carter went through to enable them to play in the playoffs. Officially, the 1988 state champions were Converse Judson, which lost 31-14 in the final to Carter. Furthermore, Carter was portrayed in the movie as a stereotypical "inner city thug" team (likely due to the shocking series of armed robberies committed by several players after the season ended); Carter at the time was located in a middle-class African-American neighborhood and was not known for dirty play.

text: The school and the city[edit]

text:
Permian was portrayed in the movie as a single large high school in a small, one-horse town in West Texas. In reality, Odessa was a city of nearly 100,000 people at the time of the events portrayed in the movie, and part of a metropolitan area of nearly 250,000 combining the populations of Midland and Ector counties. (The quaint downtown shown in the trailer for the movie was Manhattan, Kansas.) Also, Permian was (and still is) only one of two large Class 5A high schools in Odessa. The other and first high school in the city, Odessa High School (mascot: the Bronchos), was never mentioned in the movie, despite the fact that they have played Permian every year, as the two schools have been in the same UIL district since Permian opened in 1959 and shared Ratliff Stadium with Permian. An entire chapter in the book was devoted to the "Civil War" between the schools.
In the movie, Odessa was portrayed as being a mostly Anglo town with a sizable African-American population and virtually no Hispanics. In 1988, out of the almost 100,000 people that lived in Odessa, one-third were Hispanic while African-Americans made up only 5% of the population.
Ratliff Stadium was depicted as the location for Permian football practices. In reality, the team practiced mostly on campus, and the stadium, used by both Permian and Odessa, was on the outskirts of town in a fairly unpopulated area about three miles (five km) away from the Permian High campus. It was also unlikely that children would be playing touch football near the stadium, as depicted in the movie, as few houses were nearby at that time. The area around the stadium has grown dramatically since then (which caused an anachronism in the movie—the houses seen near the stadium did not yet exist in 1988).
While Ratliff Stadium has had artificial turf since its opening, in 1988 it had the original AstroTurf, not the modern FieldTurf surface seen on the stadium in the film.

text: Cameo roles[edit]

text:
Former NFL wide receiver Roy Williams (a Permian alumnus) had a cameo in the movie as an assistant coach for Midland Lee, Permian's arch-rival.
Some sequences during the state playoffs showed highlights from high school football games in Texas. In one of those highlights, NFL Pro Bowl cornerback Aqib Talib can be seen.
Ty Law played a wide receiver for Dallas Carter, the team Permian played in the movie's state championship game (as noted earlier, the real Permian-Carter game was a semifinal). He wore jersey #2, his last name was Graf, and he caught a one-handed touchdown pass.
The real James "Boobie" Miles played a Permian assistant coach in the film. Although he has no lines, he was seen several times. In the locker room scene at halftime of the state championship game, he was seen standing next to the fictional "Boobie" Miles as Coach Gaines gives his speech.

text: Soundtrack[edit]

text: The soundtrack for the film predominantly featured post-rock band Explosions in the Sky. Music by Daniel Lanois and rock band Bad Company were also included. Other songs in the film were "Just Got Paid" by ZZ Top during the montage of the Panthers' road to the finals; the pump up song featured as the team ran through the tunnel in the game against Dallas Carter was "New Noise" by the seminal Swedish punk band Refused. During the start of the third quarter during the Championship game, the song "I Wanna Be Your Dog" by The Stooges was used. Three songs from Public Enemy's album It Takes a Nation of Millions to Hold Us Back were also used prominently.

text: Reception[edit]

text: Critical reception[edit]

text: Reviews of the film were highly positive. The film received an 81% "Certified Fresh" rating on Rotten Tomatoes, based on 168 reviews, and the consensus stated: "An acute survey of the football-obsessed heartland that succeeds as both a stirring drama and a rousing sports movie."[3] The film also has a score of 70/100 on Metacritic, based on 35 reviews.[4]

text: While the residents of Odessa held a negative reception of the book, they eagerly anticipated the release of the film.[5]

text: Accolades[edit]

text: The film was recognized by American Film Institute in these lists:

text:
2004: AFI'S Top 10 Film of the Year
2008: AFI's 10 Top 10:

Nominated Sports Film[6]


document_title: The Foundation for a Better Life

question_text: who started the foundation for a better life

root

text: The Foundation for a Better Life

text: History[edit]

text: Founded in 2000, it is headed by its president, Gary Dixon. The organization launched its first campaign on November 9, 2001. The original start date was September 13, 2001, but it was postponed due to the September 11 attacks. The initial campaign appeared on about 10,000 billboards, signs and posters nationwide.[2] The original message of the campaign was modified to include themes which recognized the state of the nation following the attacks. Specifically, the values of "unity" and "courage" were added with images of flags and firefighters.[2] The campaign was created by copywriter Jay Schulberg and art director Bernie Hogya.[citation needed]

tag: p

text: Prior to the launch of the campaign, Dixon contacted Nancy Fletcher, president and chief executive at the Outdoor Advertising Association of America in Washington. He reportedly was inspired by the association's billboard campaign called God Speaks, which generated enormous attention in 1999 and 2000.[2]

text: The foundation continues to sponsor public service messages in various media. The foundation's "Pass It On" campaign has incorporated the likenesses of Wayne Gretzky, Michelle Kwan, Oprah Winfrey, Nelson Mandela, Michael J. Fox, Albert Einstein and Muhammad Ali.[3]

text: Funding[edit]

text: The Foundation neither solicits nor accepts monetary donations from the public. It is not officially affiliated with any religion, instead hoping that "the values we share transcend any particular religion or nationality". The chief contributor of the foundation also serves as the chief contributor of the Random Acts of Kindness Foundation.[4] All funding comes from the Anschutz Foundation. [5]


document_title: Diamond

question_text: where was the first diamond mined in the world

question_tokens: where was the first diamond mined in the world

text: Diamond

text: History

text: The name diamond is derived from the ancient Greek αδάμας (adámas), "proper", "unalterable", "unbreakable", "untamed", from ἀ- (a-), "un-" + δαμάω (damáō), "I overpower", "I tame".[3] Diamonds are thought to have been first recognized and mined in India, where significant alluvial deposits of the stone could be found many centuries ago along the rivers Penner, Krishna and Godavari. Diamonds have been known in India for at least 3,000 years but most likely 6,000 years.[4]

text: Diamonds have been treasured as gemstones since their use as religious icons in ancient India. Their usage in engraving tools also dates to early human history.[5][6] The popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns.[7]

text: In 1772, the French scientist Antoine Lavoisier used a lens to concentrate the rays of the sun on a diamond in an atmosphere of oxygen, and showed that the only product of the combustion was carbon dioxide, proving that diamond is composed of carbon.[8] Later in 1797, the English chemist Smithson Tennant repeated and expanded that experiment.[9] By demonstrating that burning diamond and graphite releases the same amount of gas, he established the chemical equivalence of these substances.[10]

text: The most familiar uses of diamonds today are as gemstones used for adornment, a use which dates back into antiquity, and as industrial abrasives for cutting hard materials. The dispersion of white light into spectral colors is the primary gemological characteristic of gem diamonds. In the 20th century, experts in gemology developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat (its weight), cut (quality of the cut is graded according to proportions, symmetry and polish), color (how close to white or colorless; for fancy diamonds how intense is its hue), and clarity (how free is it from inclusions).[11] A large, flawless diamond is known as a paragon.

text: Geology

text: The formation of natural diamond requires very specific conditions—exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars (4.5 and 6 GPa), but at a comparatively low temperature range between approximately 900 and 1,300 °C (1,650 and 2,370 °F). These conditions are met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.[12]

text: Formation in cratons

text: The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the requirements of temperature and pressure. These depths are estimated between 140 and 190 kilometers (87 and 118 mi) though occasionally diamonds have crystallized at depths about 300 km (190 mi).[13] The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required. The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist. Long residence in the cratonic lithosphere allows diamond crystals to grow larger.[13]

text: Through studies of carbon isotope ratios (similar to the methodology used in carbon dating, except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in diamonds comes from both inorganic and organic sources. Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction (see plate tectonics) before transforming into diamond. These two different source of carbon have measurably different 13C:12C ratios. Diamonds that have come to the Earth's surface are generally quite old, ranging from under 1 billion to 3.3 billion years old. This is 22% to 73% of the age of the Earth.[13]

text: Transport from mantle

text: Diamond-bearing rock is carried from the mantle to the Earth's surface by deep-origin volcanic eruptions. The magma for such a volcano must originate at a depth where diamonds can be formed[13]—150 km (93 mi) or more (three times or more the depth of source magma for most volcanoes). This is a relatively rare occurrence. These typically small surface volcanic craters extend downward in formations known as volcanic pipes.[13] The pipes contain material that was transported toward the surface by volcanic action, but was not ejected before the volcanic activity ceased. During eruption these pipes are open to the surface, resulting in open circulation; many xenoliths of surface rock and even wood and fossils are found in volcanic pipes. Diamond-bearing volcanic pipes are closely related to the oldest, coolest regions of continental crust (cratons). This is because cratons are very thick, and their lithospheric mantle extends to great enough depth that diamonds are stable. Not all pipes contain diamonds, and even fewer contain enough diamonds to make mining economically viable.[13]

text: The magma in volcanic pipes is usually one of two characteristic types, which cool into igneous rock known as either kimberlite or lamproite.[13] The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks (xenoliths), minerals (xenocrysts), and fluids upward. These rocks are characteristically rich in magnesium-bearing olivine, pyroxene, and amphibole minerals[13] which are often altered to serpentine by heat and fluids during and after eruption. Certain indicator minerals typically occur within diamantiferous kimberlites and are used as mineralogical tracers by prospectors, who follow the indicator trail back to the volcanic pipe which may contain diamonds. These minerals are rich in chromium (Cr) or titanium (Ti), elements which impart bright colors to the minerals. The most common indicator minerals are chromium garnets (usually bright red chromium-pyrope, and occasionally green ugrandite-series garnets), eclogitic garnets, orange titanium-pyrope, red high-chromium spinels, dark chromite, bright green chromium-diopside, glassy green olivine, black picroilmenite, and magnetite. Kimberlite deposits are known as blue ground for the deeper serpentinized part of the deposits, or as yellow ground for the near surface smectite clay and carbonate weathered and oxidized portion.[13]

text: Once diamonds have been transported to the surface by magma in a volcanic pipe, they may erode out and be distributed over a large area. A volcanic pipe containing diamonds is known as a primary source of diamonds. Secondary sources of diamonds include all areas where a significant number of diamonds have been eroded out of their kimberlite or lamproite matrix, and accumulated because of water or wind action. These include alluvial deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their size and density. Diamonds have also rarely been found in deposits left behind by glaciers (notably in Wisconsin and Indiana); in contrast to alluvial deposits, glacial deposits are minor and are therefore not viable commercial sources of diamond.[13]

text: Space diamonds

text: Not all diamonds found on Earth originated on Earth. Primitive interstellar meteorites were found to contain carbon possibly in the form of diamond.[14] A type of diamond called carbonado that is found in South America and Africa may have been deposited there via an asteroid impact (not formed from the impact) about 3 billion years ago. These diamonds may have formed in the intrastellar environment, but as of 2008, there was no scientific consensus on how carbonado diamonds originated.[15][16]

text: Diamonds can also form under other naturally occurring high-pressure conditions. Very small diamonds of micrometer and nanometer sizes, known as microdiamonds or nanodiamonds respectively, have been found in meteorite impact craters. Such impact events create shock zones of high pressure and temperature suitable for diamond formation. Impact-type microdiamonds can be used as an indicator of ancient impact craters.[12] Popigai crater in Russia may have the world's largest diamond deposit, estimated at trillions of carats, and formed by an asteroid impact.[17]

text: Scientific evidence indicates that white dwarf stars have a core of crystallized carbon and oxygen nuclei. The largest of these found in the universe so far, BPM 37093, is located 50 light-years (4.7×1014 km) away in the constellation Centaurus. A news release from the Harvard-Smithsonian Center for Astrophysics described the 2,500-mile (4,000 km)-wide stellar core as a diamond.[18]

text: Misconception about diamonds forming from compressed coal

text: Few diamonds are formed from highly compressed coal. More than 99% of diamonds ever mined have formed in the conditions of extreme heat and pressure about 90 miles (140 km) below the Earth's surface. Coal is formed from prehistoric plants buried much closer to the surface and is unlikely to migrate below 2 miles (3.2 km) through common geological processes. Most diamonds that have been dated are older than the first land plants and are therefore older than coal. It is possible that diamonds can form from coal in subduction zones and in meteoroid impacts, but diamonds formed in this way are rare, and the carbon source is more likely carbonate rocks and organic carbon in sediments, rather than coal.[19][20]

text: Material properties

text: A diamond is a transparent crystal of tetrahedrally bonded carbon atoms in a covalent network lattice (sp3) that crystallizes into the diamond lattice which is a variation of the face-centered cubic structure. Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Most notable are its extreme hardness and thermal conductivity (900–7003232000000000000♠2320 W·m−1·K−1),[21] as well as wide bandgap and high optical dispersion.[22] Above 7003197315000000000♠1700 °C (7003197300000000000♠1973 K / 7003224592777777777♠3583 °F) in vacuum or oxygen-free atmosphere, diamond converts to graphite; in air, transformation starts at ~7002973150000000000♠700 °C.[23] Diamond's ignition point is 720–7003107315000000000♠800 °C in oxygen and 850–7003127315000000000♠1000 °C in air. Naturally occurring diamonds have a density ranging from 3.15 to 7003353000000000000♠3.53 g/cm3, with pure diamond close to 7003352000000000000♠3.52 g/cm3.[1] The chemical bonds that hold the carbon atoms in diamonds together are weaker than those in graphite. In diamonds, the bonds form an inflexible three-dimensional lattice, whereas in graphite, the atoms are tightly bonded into sheets, which can slide easily over one another, making the overall structure weaker.[24] In a diamond, each carbon atom is surrounded by neighboring four carbon atoms forming a tetrahedral shaped unit.

text: Crystal habit

text: Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles. As diamond's crystal structure has a cubic arrangement of the atoms, they have many facets that belong to a cube, octahedron, rhombicosidodecahedron, tetrakis hexahedron or disdyakis dodecahedron. The crystals can have rounded off and unexpressive edges and can be elongated. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf, an opaque gum-like skin.[25]

text: Hardness

text: Diamond is the hardest known natural material on both the Vickers and the Mohs scale. Diamond's hardness has been known since antiquity, and is the source of its name.

text: Diamond hardness depends on its purity, crystalline perfection and orientation: hardness is higher for flawless, pure crystals oriented to the <111> direction (along the longest diagonal of the cubic diamond lattice).[26] Therefore, whereas it might be possible to scratch some diamonds with other materials, such as boron nitride, the hardest diamonds can only be scratched by other diamonds and nanocrystalline diamond aggregates.

text: The hardness of diamond contributes to its suitability as a gemstone. Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in engagement or wedding rings, which are often worn every day.

text: The hardest natural diamonds mostly originate from the Copeton and Bingara fields located in the New England area in New South Wales, Australia. These diamonds are generally small, perfect to semiperfect octahedra, and are used to polish other diamonds. Their hardness is associated with the crystal growth form, which is single-stage crystal growth. Most other diamonds show more evidence of multiple growth stages, which produce inclusions, flaws, and defect planes in the crystal lattice, all of which affect their hardness. It is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds that are harder than the diamonds used in hardness gauges.[27]

text: Somewhat related to hardness is another mechanical property toughness, which is a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 7.5–10 MPa·m1/2.[28][29] This value is good compared to other ceramic materials, but poor compared to most engineering materials such as engineering alloys, which typically exhibit toughnesses over 100 MPa·m1/2. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond has a cleavage plane and is therefore more fragile in some orientations than others. Diamond cutters use this attribute to cleave some stones, prior to faceting.[30] "Impact toughness" is one of the main indexes to measure the quality of synthetic industrial diamonds.

text: Pressure resistance

text: Used in so-called diamond anvil experiments to create high-pressure environments, diamonds are able to withstand crushing pressures in excess of 600 gigapascals (6 million atmospheres).[31]

text: Electrical conductivity

text: Other specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most diamonds, which are excellent electrical insulators.[32] The conductivity and blue color originate from boron impurity. Boron substitutes for carbon atoms in the diamond lattice, donating a hole into the valence band.[32]

text: Substantial conductivity is commonly observed in nominally undoped diamond grown by chemical vapor deposition. This conductivity is associated with hydrogen-related species adsorbed at the surface, and it can be removed by annealing or other surface treatments.[33][34]

text: Surface property

text: Diamonds are naturally lipophilic and hydrophobic, which means the diamonds' surface cannot be wet by water, but can be easily wet and stuck by oil. This property can be utilized to extract diamonds using oil when making synthetic diamonds. However, when diamond surfaces are chemically modified with certain ions, they are expected to become so hydrophilic that they can stabilize multiple layers of water ice at human body temperature.[35]

text: The surface of diamonds is partially oxidized. The oxidized surface can be reduced by heat treatment under hydrogen flow. That is to say, this heat treatment partially removes oxygen-containing functional groups. But diamonds (sp3C) are unstable against high temperature (above about 400 °C (752 °F)) under atmospheric pressure. The structure gradually changes into sp2C above this temperature. Thus, diamonds should be reduced under this temperature.[36]

text: Chemical stability

text: Diamonds are not very reactive. Under room temperature diamonds do not react with any chemical reagents including strong acids and bases. A diamond's surface can only be oxidized at temperatures above about 850 °C (1,560 °F) in air. Diamond also reacts with fluorine gas above about 700 °C (1,292 °F).

text: Color

text: Diamond has a wide bandgap of 6981881197067849999♠5.5 eV corresponding to the deep ultraviolet wavelength of 225 nanometers. This means that pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice is exceptionally strong, and only atoms of nitrogen, boron and hydrogen can be introduced into diamond during the growth at significant concentrations (up to atomic percents). Transition metals nickel and cobalt, which are commonly used for growth of synthetic diamond by high-pressure high-temperature techniques, have been detected in diamond as individual atoms; the maximum concentration is 0.01% for nickel[37] and even less for cobalt. Virtually any element can be introduced to diamond by ion implantation.[38]

text: Nitrogen is by far the most common impurity found in gem diamonds and is responsible for the yellow and brown color in diamonds. Boron is responsible for the blue color.[22] Color in diamond has two additional sources: irradiation (usually by alpha particles), that causes the color in green diamonds, and plastic deformation of the diamond crystal lattice. Plastic deformation is the cause of color in some brown[39] and perhaps pink and red diamonds.[40] In order of increasing rarity, yellow diamond is followed by brown, colorless, then by blue, green, black, pink, orange, purple, and red.[30] "Black", or Carbonado, diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause the coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice, known as a carbon flaw. The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present.[30] The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in the normal color range, and applies a grading scale from "D" (colorless) to "Z" (light yellow). Diamonds of a different color, such as blue, are called fancy colored diamonds and fall under a different grading scale.[30]

text: In 2008, the Wittelsbach Diamond, a 35.56-carat (7.112 g) blue diamond once belonging to the King of Spain, fetched over US$24 million at a Christie's auction.[41] In May 2009, a 7.03-carat (1.406 g) blue diamond fetched the highest price per carat ever paid for a diamond when it was sold at auction for 10.5 million Swiss francs (6.97 million euros, or US$9.5 million at the time).[42] That record was, however, beaten the same year: a 5-carat (1.0 g) vivid pink diamond was sold for $10.8 million in Hong Kong on December 1, 2009.[43]

text: Identification

text: Diamonds can be identified by their high thermal conductivity. Their high refractive index is also indicative, but other materials have similar refractivity. Diamonds cut glass, but this does not positively identify a diamond because other materials, such as quartz, also lie above glass on the Mohs scale and can also cut it. Diamonds can scratch other diamonds, but this can result in damage to one or both stones. Hardness tests are infrequently used in practical gemology because of their potentially destructive nature.[44] The extreme hardness and high value of diamond means that gems are typically polished slowly, using painstaking traditional techniques and greater attention to detail than is the case with most other gemstones;[10] these tend to result in extremely flat, highly polished facets with exceptionally sharp facet edges. Diamonds also possess an extremely high refractive index and fairly high dispersion. Taken together, these factors affect the overall appearance of a polished diamond and most diamantaires still rely upon skilled use of a loupe (magnifying glass) to identify diamonds "by eye".[45]

text: Industry

text: The diamond industry can be separated into two distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. Both markets value diamonds differently.

text: Gem-grade diamonds

text: A large trade in gem-grade diamonds exists. Although most gem-grade diamonds are sold newly polished, there is a well-established market for resale of polished diamonds (e.g. pawnbroking, auctions, second-hand jewelry stores, diamantaires, bourses, etc.). One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to just a few locations; in 2003, 92% of the world's diamonds were cut and polished in Surat, India.[46] Other important centers of diamond cutting and trading are the Antwerp diamond district in Belgium, where the International Gemological Institute is based, London, the Diamond District in New York City, the Diamond Exchange District in Tel Aviv, and Amsterdam. One contributory factor is the geological nature of diamond deposits: several large primary kimberlite-pipe mines each account for significant portions of market share (such as the Jwaneng mine in Botswana, which is a single large-pit mine that can produce between 12,500,000 and 15,000,000 carats (2,500 and 3,000 kg) of diamonds per year[47]). Secondary alluvial diamond deposits, on the other hand, tend to be fragmented amongst many different operators because they can be dispersed over many hundreds of square kilometers (e.g., alluvial deposits in Brazil).

text: The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers, the most important being Antwerp, where 80% of all rough diamonds, 50% of all cut diamonds and more than 50% of all rough, cut and industrial diamonds combined are handled.[48] This makes Antwerp a de facto "world diamond capital".[49] The city of Antwerp also hosts the Antwerpsche Diamantkring, created in 1929 to become the first and biggest diamond bourse dedicated to rough diamonds.[50] Another important diamond center is New York City, where almost 80% of the world's diamonds are sold, including auction sales.[48]

text: The De Beers company, as the world's largest diamond mining company, holds a dominant position in the industry, and has done so since soon after its founding in 1888 by the British imperialist Cecil Rhodes. De Beers is currently the world's largest operator of diamond production facilities (mines) and distribution channels for gem-quality diamonds. The Diamond Trading Company (DTC) is a subsidiary of De Beers and markets rough diamonds from De Beers-operated mines. De Beers and its subsidiaries own mines that produce some 40% of annual world diamond production. For most of the 20th century over 80% of the world's rough diamonds passed through De Beers,[51] but by 2001–2009 the figure had decreased to around 45%,[52] and by 2013 the company's market share had further decreased to around 38% in value terms and even less by volume.[53] De Beers sold off the vast majority of its diamond stockpile in the late 1990s – early 2000s[54] and the remainder largely represents working stock (diamonds that are being sorted before sale).[55] This was well documented in the press[56] but remains little known to the general public.

text: As a part of reducing its influence, De Beers withdrew from purchasing diamonds on the open market in 1999 and ceased, at the end of 2008, purchasing Russian diamonds mined by the largest Russian diamond company Alrosa.[57] As of January 2011, De Beers states that it only sells diamonds from the following four countries: Botswana, Namibia, South Africa and Canada.[58] Alrosa had to suspend their sales in October 2008 due to the global energy crisis,[59] but the company reported that it had resumed selling rough diamonds on the open market by October 2009.[60] Apart from Alrosa, other important diamond mining companies include BHP Billiton, which is the world's largest mining company;[61] Rio Tinto Group, the owner of the Argyle (100%), Diavik (60%), and Murowa (78%) diamond mines;[62] and Petra Diamonds, the owner of several major diamond mines in Africa.

text: Further down the supply chain, members of The World Federation of Diamond Bourses (WFDB) act as a medium for wholesale diamond exchange, trading both polished and rough diamonds. The WFDB consists of independent diamond bourses in major cutting centers such as Tel Aviv, Antwerp, Johannesburg and other cities across the USA, Europe and Asia.[30] In 2000, the WFDB and The International Diamond Manufacturers Association established the World Diamond Council to prevent the trading of diamonds used to fund war and inhumane acts. WFDB's additional activities include sponsoring the World Diamond Congress every two years, as well as the establishment of the International Diamond Council (IDC) to oversee diamond grading.

text: Once purchased by Sightholders (which is a trademark term referring to the companies that have a three-year supply contract with DTC), diamonds are cut and polished in preparation for sale as gemstones ('industrial' stones are regarded as a by-product of the gemstone market; they are used for abrasives).[63] The cutting and polishing of rough diamonds is a specialized skill that is concentrated in a limited number of locations worldwide.[63] Traditional diamond cutting centers are Antwerp, Amsterdam, Johannesburg, New York City, and Tel Aviv. Recently, diamond cutting centers have been established in China, India, Thailand, Namibia and Botswana.[63] Cutting centers with lower cost of labor, notably Surat in Gujarat, India, handle a larger number of smaller carat diamonds, while smaller quantities of larger or more valuable diamonds are more likely to be handled in Europe or North America. The recent expansion of this industry in India, employing low cost labor, has allowed smaller diamonds to be prepared as gems in greater quantities than was previously economically feasible.[48]

text: Diamonds prepared as gemstones are sold on diamond exchanges called bourses. There are 28 registered diamond bourses in the world.[64] Bourses are the final tightly controlled step in the diamond supply chain; wholesalers and even retailers are able to buy relatively small lots of diamonds at the bourses, after which they are prepared for final sale to the consumer. Diamonds can be sold already set in jewelry, or sold unset ("loose"). According to the Rio Tinto Group, in 2002 the diamonds produced and released to the market were valued at US$9 billion as rough diamonds, US$14 billion after being cut and polished, US$28 billion in wholesale diamond jewelry, and US$57 billion in retail sales.[65]

text: Cutting

text: Mined rough diamonds are converted into gems through a multi-step process called "cutting". Diamonds are extremely hard, but also brittle and can be split up by a single blow. Therefore, diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a faceted jewel where the specific angles between the facets would optimize the diamond luster, that is dispersion of white light, whereas the number and area of facets would determine the weight of the final product. The weight reduction upon cutting is significant and can be of the order of 50%.[66] Several possible shapes are considered, but the final decision is often determined not only by scientific, but also practical considerations. For example, the diamond might be intended for display or for wear, in a ring or a necklace, singled or surrounded by other gems of certain color and shape.[67] Some of them may be considered as classical, such as round, pear, marquise, oval, hearts and arrows diamonds, etc. Some of them are special, produced by certain companies, for example, Phoenix, Cushion, Sole Mio diamonds, etc.[68]

text: The most time-consuming part of the cutting is the preliminary analysis of the rough stone. It needs to address a large number of issues, bears much responsibility, and therefore can last years in case of unique diamonds. The following issues are considered:

text:
The hardness of diamond and its ability to cleave strongly depend on the crystal orientation. Therefore, the crystallographic structure of the diamond to be cut is analyzed using X-ray diffraction to choose the optimal cutting directions.
Most diamonds contain visible non-diamond inclusions and crystal flaws. The cutter has to decide which flaws are to be removed by the cutting and which could be kept.
The diamond can be split by a single, well calculated blow of a hammer to a pointed tool, which is quick, but risky. Alternatively, it can be cut with a diamond saw, which is a more reliable but tedious procedure.[67][69]

tag: ul

text: After initial cutting, the diamond is shaped in numerous stages of polishing. Unlike cutting, which is a responsible but quick operation, polishing removes material by gradual erosion and is extremely time consuming. The associated technique is well developed; it is considered as a routine and can be performed by technicians.[70] After polishing, the diamond is reexamined for possible flaws, either remaining or induced by the process. Those flaws are concealed through various diamond enhancement techniques, such as repolishing, crack filling, or clever arrangement of the stone in the jewelry. Remaining non-diamond inclusions are removed through laser drilling and filling of the voids produced.[44]

text: Marketing

text: Marketing has significantly affected the image of diamond as a valuable commodity.

text: N. W. Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market. And the firm created new markets in countries where no diamond tradition had existed before. N. W. Ayer's marketing included product placement, advertising focused on the diamond product itself rather than the De Beers brand, and associations with celebrities and royalty. Without advertising the De Beers brand, De Beers was advertising its competitors' diamond products as well,[71] but this was not a concern as De Beers dominated the diamond market throughout the 20th century. De Beers' market share dipped temporarily to 2nd place in the global market below Alrosa in the aftermath of the global economic crisis of 2008, down to less than 29% in terms of carats mined, rather than sold.[72] The campaign lasted for decades but was effectively discontinued by early 2011. De Beers still advertises diamonds, but the advertising now mostly promotes its own brands, or licensed product lines, rather than completely "generic" diamond products.[72] The campaign was perhaps best captured by the slogan "a diamond is forever".[7] This slogan is now being used by De Beers Diamond Jewelers,[73] a jewelry firm which is a 50%/50% joint venture between the De Beers mining company and LVMH, the luxury goods conglomerate.

text: Brown-colored diamonds constituted a significant part of the diamond production, and were predominantly used for industrial purposes. They were seen as worthless for jewelry (not even being assessed on the diamond color scale). After the development of Argyle diamond mine in Australia in 1986, and marketing, brown diamonds have become acceptable gems.[74][75] The change was mostly due to the numbers: the Argyle mine, with its 35,000,000 carats (7,000 kg) of diamonds per year, makes about one-third of global production of natural diamonds;[76] 80% of Argyle diamonds are brown.[77]

text: Industrial-grade diamonds

text: Industrial diamonds are valued mostly for their hardness and thermal conductivity, making many of the gemological characteristics of diamonds, such as the 4 Cs, irrelevant for most applications. 80% of mined diamonds (equal to about 135,000,000 carats (27,000 kg) annually) are unsuitable for use as gemstones and are used industrially.[78] In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 570,000,000 carats (114,000 kg) of synthetic diamond is produced annually for industrial use (in 2004; in 2014 it is 4,500,000,000 carats (900,000 kg), 90% of which is produced in China). Approximately 90% of diamond grinding grit is currently of synthetic origin.[79]

text: The boundary between gem-quality diamonds and industrial diamonds is poorly defined and partly depends on market conditions (for example, if demand for polished diamonds is high, some lower-grade stones will be polished into low-quality or small gemstones rather than being sold for industrial use). Within the category of industrial diamonds, there is a sub-category comprising the lowest-quality, mostly opaque stones, which are known as bort.[80]

text: Industrial use of diamonds has historically been associated with their hardness, which makes diamond the ideal material for cutting and grinding tools. As the hardest known naturally occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. Common industrial applications of this property include diamond-tipped drill bits and saws, and the use of diamond powder as an abrasive. Less expensive industrial-grade diamonds, known as bort, with more flaws and poorer color than gems, are used for such purposes.[81] Diamond is not suitable for machining ferrous alloys at high speeds, as carbon is soluble in iron at the high temperatures created by high-speed machining, leading to greatly increased wear on diamond tools compared to alternatives.[82]

text: Specialized applications include use in laboratories as containment for high-pressure experiments (see diamond anvil cell), high-performance bearings, and limited use in specialized windows.[80] With the continuing advances being made in the production of synthetic diamonds, future applications are becoming feasible. The high thermal conductivity of diamond makes it suitable as a heat sink for integrated circuits in electronics.[83]

text: Mining

text: Approximately 130,000,000 carats (26,000 kg) of diamonds are mined annually, with a total value of nearly US$9 billion, and about 100,000 kg (220,000 lb) are synthesized annually.[84]

text: Roughly 49% of diamonds originate from Central and Southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia.[79] They are mined from kimberlite and lamproite volcanic pipes, which can bring diamond crystals, originating from deep within the Earth where high pressures and temperatures enable them to form, to the surface. The mining and distribution of natural diamonds are subjects of frequent controversy such as concerns over the sale of blood diamonds or conflict diamonds by African paramilitary groups.[85] The diamond supply chain is controlled by a limited number of powerful businesses, and is also highly concentrated in a small number of locations around the world.

text: Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed, during which care is required not to destroy larger diamonds, and then sorted by density. Today, diamonds are located in the diamond-rich density fraction with the help of X-ray fluorescence, after which the final sorting steps are done by hand. Before the use of X-rays became commonplace,[66] the separation was done with grease belts; diamonds have a stronger tendency to stick to grease than the other minerals in the ore.[30]

text: Historically, diamonds were found only in alluvial deposits in Guntur and Krishna district of the Krishna River delta in Southern India.[86] India led the world in diamond production from the time of their discovery in approximately the 9th century BC[4][87] to the mid-18th century AD, but the commercial potential of these sources had been exhausted by the late 18th century and at that time India was eclipsed by Brazil where the first non-Indian diamonds were found in 1725.[4] Currently, one of the most prominent Indian mines is located at Panna.[88]

text: Diamond extraction from primary deposits (kimberlites and lamproites) started in the 1870s after the discovery of the Diamond Fields in South Africa.[89] Production has increased over time and now an accumulated total of 4,500,000,000 carats (900,000 kg) have been mined since that date.[90] Twenty percent of that amount has been mined in the last five years, and during the last 10 years, nine new mines have started production; four more are waiting to be opened soon. Most of these mines are located in Canada, Zimbabwe, Angola, and one in Russia.[90]

text: In the U.S., diamonds have been found in Arkansas, Colorado, New Mexico, Wyoming, and Montana.[91][92] In 2004, the discovery of a microscopic diamond in the U.S. led to the January 2008 bulk-sampling of kimberlite pipes in a remote part of Montana. The Crater of Diamonds State Park in Arkansas is open to the public, and is the only mine in the world where members of the public can dig for diamonds.[92]

text: Today, most commercially viable diamond deposits are in Russia (mostly in Sakha Republic, for example Mir pipe and Udachnaya pipe), Botswana, Australia (Northern and Western Australia) and the Democratic Republic of the Congo.[93] In 2005, Russia produced almost one-fifth of the global diamond output, according to the British Geological Survey. Australia boasts the richest diamantiferous pipe, with production from the Argyle diamond mine reaching peak levels of 42 metric tons per year in the 1990s.[91][94] There are also commercial deposits being actively mined in the Northwest Territories of Canada and Brazil.[79] Diamond prospectors continue to search the globe for diamond-bearing kimberlite and lamproite pipes.

text: Political issues

text: In some of the more politically unstable central African and west African countries, revolutionary groups have taken control of diamond mines, using proceeds from diamond sales to finance their operations. Diamonds sold through this process are known as conflict diamonds or blood diamonds.[85] Major diamond trading corporations continue to fund and fuel these conflicts by doing business with armed groups.[citation needed]

text: In response to public concerns that their diamond purchases were contributing to war and human rights abuses in central and western Africa, the United Nations, the diamond industry and diamond-trading nations introduced the Kimberley Process in 2002.[95] The Kimberley Process aims to ensure that conflict diamonds do not become intermixed with the diamonds not controlled by such rebel groups. This is done by requiring diamond-producing countries to provide proof that the money they make from selling the diamonds is not used to fund criminal or revolutionary activities. Although the Kimberley Process has been moderately successful in limiting the number of conflict diamonds entering the market, some still find their way in. According to the International Diamond Manufacturers Association, conflict diamonds constitute 2–3% of all diamonds traded.[96] Two major flaws still hinder the effectiveness of the Kimberley Process: (1) the relative ease of smuggling diamonds across African borders, and (2) the violent nature of diamond mining in nations that are not in a technical state of war and whose diamonds are therefore considered "clean".[95]

text: The Canadian Government has set up a body known as the Canadian Diamond Code of Conduct[97] to help authenticate Canadian diamonds. This is a stringent tracking system of diamonds and helps protect the "conflict free" label of Canadian diamonds.[98]

text: Synthetics, simulants, and enhancements

text: Synthetics

text: Synthetic diamonds are diamonds manufactured in a laboratory, as opposed to diamonds mined from the Earth. The gemological and industrial uses of diamond have created a large demand for rough stones. This demand has been satisfied in large part by synthetic diamonds, which have been manufactured by various processes for more than half a century. However, in recent years it has become possible to produce gem-quality synthetic diamonds of significant size.[13] It is possible to make colorless synthetic gemstones that, on a molecular level, are identical to natural stones and so visually similar that only a gemologist with special equipment can tell the difference.[99]

text: The majority of commercially available synthetic diamonds are yellow and are produced by so-called high-pressure high-temperature (HPHT) processes.[100] The yellow color is caused by nitrogen impurities. Other colors may also be reproduced such as blue, green or pink, which are a result of the addition of boron or from irradiation after synthesis.[101]

text: Another popular method of growing synthetic diamond is chemical vapor deposition (CVD). The growth occurs under low pressure (below atmospheric pressure). It involves feeding a mixture of gases (typically 1 to 99 methane to hydrogen) into a chamber and splitting them to chemically active radicals in a plasma ignited by microwaves, hot filament, arc discharge, welding torch or laser.[102] This method is mostly used for coatings, but can also produce single crystals several millimeters in size (see picture).[84]

text: As of 2010, nearly all 5,000 million carats (1,000 tonnes) of synthetic diamonds produced per year are for industrial use. Around 50% of the 133 million carats of natural diamonds mined per year end up in industrial use.[99][103] Mining companies' expenses average $40 to $60 per carat for natural colorless diamonds, while synthetic manufacturers' expenses average $2,500 per carat for synthetic, gem-quality colorless diamonds.[99]:79 However, a purchaser is more likely to encounter a synthetic when looking for a fancy-colored diamond because nearly all synthetic diamonds are fancy-colored, while only 0.01% of natural diamonds are.[104]

text: Simulants

text: A diamond simulant is a non-diamond material that is used to simulate the appearance of a diamond, and may be referred to as diamante. Cubic zirconia is the most common. The gemstone moissanite (silicon carbide) can be treated as a diamond simulant, though more costly to produce than cubic zirconia. Both are produced synthetically.[105]

text: Enhancements

text: Diamond enhancements are specific treatments performed on natural or synthetic diamonds (usually those already cut and polished into a gem), which are designed to better the gemological characteristics of the stone in one or more ways. These include laser drilling to remove inclusions, application of sealants to fill cracks, treatments to improve a white diamond's color grade, and treatments to give fancy color to a white diamond.[106]

text: Coatings are increasingly used to give a diamond simulant such as cubic zirconia a more "diamond-like" appearance. One such substance is diamond-like carbon—an amorphous carbonaceous material that has some physical properties similar to those of the diamond. Advertising suggests that such a coating would transfer some of these diamond-like properties to the coated stone, hence enhancing the diamond simulant. Techniques such as Raman spectroscopy should easily identify such a treatment.[107]

text: Identification

text: Early diamond identification tests included a scratch test relying on the superior hardness of diamond. This test is destructive, as a diamond can scratch another diamond, and is rarely used nowadays. Instead, diamond identification relies on its superior thermal conductivity. Electronic thermal probes are widely used in the gemological centers to separate diamonds from their imitations. These probes consist of a pair of battery-powered thermistors mounted in a fine copper tip. One thermistor functions as a heating device while the other measures the temperature of the copper tip: if the stone being tested is a diamond, it will conduct the tip's thermal energy rapidly enough to produce a measurable temperature drop. This test takes about 2–3 seconds.[108]

text: Whereas the thermal probe can separate diamonds from most of their simulants, distinguishing between various types of diamond, for example synthetic or natural, irradiated or non-irradiated, etc., requires more advanced, optical techniques. Those techniques are also used for some diamonds simulants, such as silicon carbide, which pass the thermal conductivity test. Optical techniques can distinguish between natural diamonds and synthetic diamonds. They can also identify the vast majority of treated natural diamonds.[109] "Perfect" crystals (at the atomic lattice level) have never been found, so both natural and synthetic diamonds always possess characteristic imperfections, arising from the circumstances of their crystal growth, that allow them to be distinguished from each other.[110]

text: Laboratories use techniques such as spectroscopy, microscopy and luminescence under shortwave ultraviolet light to determine a diamond's origin.[109] They also use specially made instruments to aid them in the identification process. Two screening instruments are the DiamondSure and the DiamondView, both produced by the DTC and marketed by the GIA.[111]

text: Several methods for identifying synthetic diamonds can be performed, depending on the method of production and the color of the diamond. CVD diamonds can usually be identified by an orange fluorescence. D-J colored diamonds can be screened through the Swiss Gemmological Institute's[112] Diamond Spotter. Stones in the D-Z color range can be examined through the DiamondSure UV/visible spectrometer, a tool developed by De Beers.[110] Similarly, natural diamonds usually have minor imperfections and flaws, such as inclusions of foreign material, that are not seen in synthetic diamonds.

text: Screening devices based on diamond type detection can be used to make a distinction between diamonds that are certainly natural and diamonds that are potentially synthetic. Those potentially synthetic diamonds require more investigation in a specialized lab. Examples of commercial screening devices are D-Screen (WTOCD / HRD Antwerp) and Alpha Diamond Analyzer (Bruker / HRD Antwerp).

text: Stolen diamonds

text: Occasionally large thefts of diamonds take place. In February 2013 armed robbers carried out a raid at Brussels Airport and escaped with gems estimated to be worth $50m (£32m; 37m euros). The gang broke through a perimeter fence and raided the cargo hold of a Swiss-bound plane. The gang have since been arrested and large amounts of cash and diamonds recovered.[113]

text: The identification of stolen diamonds presents a set of difficult problems. Rough diamonds will have a distinctive shape depending on whether their source is a mine or from an alluvial environment such as a beach or river - alluvial diamonds have smoother surfaces than those that have been mined. Determining the provenance of cut and polished stones is much more complex.

text: The Kimberley Process was developed to monitor the trade in rough diamonds and prevent their being used to fund violence. Before exporting, rough diamonds are certificated by the government of the country of origin. Some countries, such as Venezuela, are not party to the agreement. The Kimberley Process does not apply to local sales of rough diamonds within a country.

text: Diamonds may be etched by laser with marks invisible to the naked eye. Lazare Kaplan, a US-based company, developed this method. However, whatever is marked on a diamond can readily be removed.[114][115]