Ford Crown Victoria

Another rumor going around at Ford is that the Crown Victoria will eventually be replaced by one of two vehicles:. In addition, diamonds are the subject of various myths and legends. Ford has denied this. Clarke's 2061: Odyssey Three (1988) and Neal Stephenson's The Diamond Age (1995). Ford was rumored to be considering replacing the aging Panther platform with the front or all-wheel drive platform based on the D3 architecture. Notable pieces of fiction include Ian Fleming's Diamonds Are Forever (1956), Arthur C. The code appears in the Vehicle Identification Number and distinguishes it from the commercial (P72), standard civilian (P73) and luxury civilian (P74) models. Diamonds are a common focus of fiction.

"P71" is the designation for the Police Interceptor. The diamond is the birthstone for people born in the month of April, and is also used as the symbol of a sixty-year anniversary, such as a Diamond Jubilee (see hierarchy of precious substances). Luckily, this was only for very early 2003 models as the problems appear to have been fixed for newer models. However, many people feel very uncomfortable at the thought of wearing the carbonized remains of people as jewelry. Some 2003 Mercury Marauders were also affected. The LifeGem company further taps modern symbolism by offering to synthetically convert the carbonized remains of people or pets into "memorial diamonds". This was not limited to the Crown Victoria Police Interceptor. The Mattachine Society, one of the first and the foremost gay rights groups in the United States, used so-called harlequin diamonds (four smaller diamonds arranged in a pattern to form one larger diamond) as their emblem.

The newly designed steel wheels would rust and fall out, the rack and pinion units would fail early (sub-10k miles), and the rear axles would wear out and possibly fall out as well. Diamonds were also a symbol of gay community in the 1950s. There were some problems with early 2003 Police Interceptor. Inaccessibility of diamonds to the vast majority of the population limited the popularity of diamonds as betrothal jewels during this period. Following the criticism of fires following rear-end collisions, Crown Victoria Police Interceptors now come with an automatic fire suppression system and special "trunk packs" designed to help prevent trunk contents from piercing the fuel tank in a collision. 1430–40), a pictorial piece depicting a wedding couple. Kevlar-lined doors, which might be useful as protective barriers during gun fights, are optional on the Crown Victoria Police Interceptors. 1370–80) and the Heftlein brooch of Vienna (ca.

P71 zip tube (the flexible rubber hose between the throttle body and MAF outlet) is also used to reduce NVH (Noise, Vibration, and Harshness) as well as transfer air from the airbox to the throttle body with minimal flow resistance. Other early examples of betrothal jewels incorporating diamonds include the Bridal Crown of Blanche (ca. This allows for much more precise flow calibration and reduces the chances of air leakage. It can be traced to the marriage of Maximilian I (then Archduke of Austria) to Mary of Burgundy in 1477. This includes a new air box that resembles the Mercury Marauder airbox (raised airbox lid, deeper bottom) with an integrated 80mm mass air flow (MAF) sensor that is part of the airbox lid. The diamond engagement ring is, however, not an original invention of De Beers. The 2004-2005 Police Interceptor (referred to many as CVPIs, P71s) are rated for 250 hp (186 kW) because of the addition of a new air intake system. The popularity of this modern tradition can be traced directly to the marketing campaigns of De Beers, starting in 1938.

Another difference between the civilian version and the Police Interceptor is that the back seats of the latter are built with the back and bottom portions as a single piece with no space in between them for back-seat occupants to hide objects. Today, diamonds are used to symbolize eternity and love, being often seen adorning engagement rings and sometimes wedding rings as well. Further refinements were made in 2001, including deletion of all trim on the plastic bumper pieces, and a honeycomb-style grille, replacing a slat-style grille as is found on standard Crown Victorias. In Western culture, diamonds are the traditional emblem of fearlessness and virtue, but have also often associated with power, wealth, crime and misfortune. The changes made in 1999 included a new rear fascia insignia, an all-black trim scheme which included replacing the color-keyed trunklid panels with black ones, and a black grille. In Tibetan Buddhism, also known as Vajrayana (Diamond Vehicle), diamonds are an important symbol, and the Diamond Sutra is one of the most popular texts. Prior to 1999, the police cars were officially known as the P71 Crown Victoria. Many long dead cultures have sought to explain diamond's superlative properties through divine or mystical affiliations.

The law enforcement version of the 1999-up Crown Victoria is known as the Police Interceptor, and many taxi companies use this "heavy duty" version as well. It is said the Greeks believed diamonds were tears of the gods; the Romans believed they were splinters of fallen stars. The Marauder was not a market success and the model was retired after just two years of production. The point at which diamonds began to be associated with divinity is not known, but early texts indicate that it was recognized in India since at least 400 BCE. Mercury introduced a performance version called the Mercury Marauder but sales were slow. The diamonds themselves were thought to be endowments from the gods and were therefore cherished. This construction style is opposed to the now more commonly used unibody construction style where the body panels are load-bearing members. Perhaps the earliest symbolic use of diamonds was as the eyes of Hindu devotional statues.

The Ford Crown Victoria, Mercury Grand Marquis, and the Lincoln Town Car are the only mass-produced passenger cars with body-on-frame construction in the United States. Because of their extraordinary physical properties, diamonds have been used symbolically since near the time of their first discovery. Although the company has avoided financial responsibility for the fires, the components found in Ford's fuel tank safety kits have been in use with Ford vehicles since the early 1980s as evidenced in the 1980-1982 Ford Thunderbird that has a polymer differential cover shield and lower shock mount shields to prevent the fuel tank from contacting those areas. However, synthetic diamonds may one day be indistinguishable from natural diamonds, and new techniques for simulants (such as coating them with a very thin diamond-like layer of carbon) are making it harder to easily distinguish between simulants and real diamonds. An attempted class-action suit in Belvidere, Illinois in 2004 failed as well. The established natural diamond industry has a vested interest in maintaining the distinction between natural diamonds and other diamonds, and has made significant investments toward that end. Despite numerous court cases charging Ford with partial liability for fires caused in accidents, the company has never been convicted. Currently, trained gemologists with appropriate equipment are able to distinguish natural diamonds from all synthetic and simulant diamonds, and identify all enhanced natural diamonds.

It should also be noted then every other car on the road has the same "flaw", but civilians do not routinely park on the shoulder of high speed interstate highways, where they would be subject to a collision that can cause a fuel tank to erupt. 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. Even though this model of the Crown Victoria has been criticized for this type of rear end collision, the civilian Panthers all have the same "flaw" and Ford refuses to address this problem on all the models. Diamond enhancements are specific treatments, performed on natural 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 items were removed on later models, however. Both CZ and moissanite are synthetically produced for use as a diamond simulant. Ford also used polymer shock bolt covers for the lower mounts on the rear shocks. The most familiar diamond simulant to most consumers is cubic zirconia (commonly abbreviated as CZ); recently moissanite has also gained cachet as a popular diamond simulant.

Ford used polymer shields on the gas tank facing the rear differential covers. Materials which have similar gemological characteristics to diamond but are not real mined or synthetic diamond are known as diamond simulants. It is interesting to mention the contents of the recall kit because they can be found on early 1980s Fords. A diamond's gem quality, which is not as dependent on material properties as industrial applications, has invited both imitation and the invention of procedures to enhance the gemological properties of natural diamonds. Ford's solution in the form of a recall kit includes appliques to mark unsafe areas to drill in the luggage compartment, as well as a rear differential cover shield, and rear shock lower bolt shields. Diamonds have been manufactured synthetically for over fifty years. The equipment installers would then install bolts that go into the gas tank and can cause sparking in an accident. This process has historically produced industrial-grade diamonds, but synthetic diamond producers have recently begun to penetrate the gem diamond market.

Due to the gas tank's orientation, drilling through the package tray will result in drilling into the gas tank. A portion of this demand is now being met by synthetic diamonds, man-made diamonds which have similar properties to natural diamonds. The condition may have been exacerbated by police equipment installers drilling over the package tray in the luggage compartment. The gemological and industrial uses of diamond have created a large demand for raw stones. There are very few, if any, reports for this fire problem when struck at ordinary speeds. [4]. In the case of the Crown Victoria, it is a combination of factors including a number of different traits, such as the nature and position of the gas tank, and the unique circumstances of the car crashes, namely at speeds of over 85 miles and hour, something most civilians would never be subjected to. 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 retail sales of US$57 billion.

In fact the survival rate for these type of collisions was higher than any other mid-sized sedan, which perform worse due to their much lighter construction, lower weight, and shorter distance for a crumple zone. Diamonds can be sold already set in jewelry, or as is increasingly popular, sold unset ("loose"). However, the safety ratings are still higher than most other american vehicles at this price point. This is 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. While the car has been highly rated for safety, there was some controversy and lawsuits in the 1990s over the car's gas tank leaking after certain types of high energy impacts, specifically when being hit at a certain angle offset in the rear at speeds greater than 85 mph (137 km/h). There are 24 registered diamond bourses. Engines:. Diamonds which have been prepared as gemstones are sold on diamond exchanges called bourses.

It also offers more interior space and slightly better fuel economy than many SUVs of similar weight. The recent expansion of this industry in India, employing low cost labor, has allowed smaller diamonds to be prepared as gems than was previously economically feasible. It is considerably more durable than modern front wheel drive cars that rely on constant velocity joints for transmission of power to the steering wheels. Demonstrating this, India produces 90% of all cut and polished diamonds by number, but only 55% by value. The Crown Victoria has often characterized as an "older person's car", but this is a misconception considering nearly all vehicles in this class tend to have an older client base (largely due to economic reasons). Cutting centers with lower costs 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 design has been popular with police departments and cab companies to the same extent as the Chevrolet Caprice in the 1980s and early 1990s, especially in New York City where they make up the majority of the taxi and New York City Police Department fleets, as well among the general populace. Recently, diamond cutting centers have been established in China, India, and Thailand.

It still uses a front independent suspension with a rear live axle on a body on frame design, using a traditional rear wheel drive drivetrain. Traditional diamond cutting centers are Antwerp, Amsterdam, Johannesburg, New York, and Tel Aviv. Even with the latest 2006 Crown Victoria, the overall design remains relatively unchanged from the 1979 design. The cutting and polishing of rough diamonds is a specialized skill that is concentrated in a limited number of locations worldwide. 2005 models also received a new steering wheel. Once purchased by sightholders, diamonds are cut and polished in preparation for sale as gemstones. The Crown Victoria retained the same exterior styling, but 2005 models received a rear whip radio antenna rather than an integrated rear defroster antenna. DTC performs sophisticated sorting of rough diamonds into over 16,000 categories, and then sells bulk lots of rough diamonds to a limited number of sightholders a few times a year.

The engine output increased due to the addition of a knock sensor for more aggressive timing. The Diamond Trading Company, or DTC, is a subsidiary of De Beers and markets rough diamonds produced both by De Beers mines and other mines from which it purchases rough diamond production; in whole, about two thirds of all rough diamonds pass through the company. As a result, the road-handling manners of the Panther platform cars have improved significantly. In 2003, this constituted total production of nearly US$9 billion in value. The rear suspension was redone for durability in police-duty applications and the rear shocks were moved outboard of the frame rails for better handling and ease of maintenance. Currently, gem production totals nearly 30 million carats (6,000 kg) of cut and polished stones annually, and over 100 million carats (20,000 kg) of diamonds are sold for industrial use each year. In the front, new aluminum control arms, and rack and pinion steering (replacing the recirculating ball units) have been implemented. Although the Kimberly Process has been somewhat successful in limiting the number of conflict diamonds entering the market, conflict diamonds smuggled to market continue to persist to some degree.

New inverted monotube shocks are now used (replacing the old twin-tube shocks that had been around since the 1960s). The Kimberley Process provides documentation and certification of diamond exports from producing countries to ensure that the proceeds of sale are not being used to fund criminal or revolutionary activities. The front and rear suspension was also completely overhauled. In response to public concerns that their diamond purchases were contributing to war and human rights abuses in central Africa and west Africa, the diamond industry and diamond-trading nations introduced the Kimberley Process in 2002, which is aimed at ensuring that conflict diamonds do not become intermixed with the diamonds not controlled by such rebel groups. In 2003, the chassis was again redone with hydroformed steel. Diamonds sold through this process are known as conflict diamonds or blood diamonds. The Crown Vic's twins, the Mercury Grand Marquis and Lincoln Town Car, however, are still available in Canada. 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.

Civilians can, however, purchase used 2000 & up Crown Victorias that are available at dealerships every so often. Diamond prospectors continue to search the globe for diamond-bearing kimberlite and lamproite pipes. The basic civilian Crown Victoria is only available when ordered as a fleet and is not available through Ford dealerships. There are also commercial deposits being actively mined in the Northwest Territories of Canada, Siberia (mostly in Yakutia territory, for example Mir pipe and Udachnaya pipe), Brazil, and in Northern and Western Australia. Since 2000, the Crown Victoria has only been available in Canada as a Police Interceptor for law enforcement, or as a Taxi or Special Service Vehicle for commercial fleets. Today, most commercially viable diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, Angola and Sierra Leone. In Canada, 1999 was the last year the Crown Victoria was individually available to civilians from Ford dealerships. The first non-Indian diamond source was found in Brazil in 1725.

The Crown Victoria also features a 114.7" wheelbase. Historically diamonds were known to be found only in alluvial deposits in southern India; India led the world in diamond production from the time of their discovery in approximately the 9th century BCE to the mid-18th century CE, but the commercial potential of these sources has been exhausted. This design, already being used on the 1996-1999 Ford Taurus SHO 3.4L V8 engine, was later implemented on other users of the Modular V8, including the 1999-up Mustang GT, and many F/E-series trucks. The concentration of power only loosens at the retail level, where diamonds are sold by a limited number of distributors, known as sightholders, to jewelers around the world. The Crown Victoria also uses a coil-on-plug ignition design rather than traditional spark plug wires. In fact, the amount of power which De Beers has consolidated historically prevented it from direct trade with the United States, as its trade practices led to an indictment for violating antitrust regulations (the case was settled in 2004). The general road handling manners have improved, but towing capacity has been reduced. 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.

The 1998-2002 "Crown Vics" have a revised 4-link rear suspension with a Watts linkage. See also: List of diamond mines. In 1998, the Crown Victoria's exterior styling, rear suspension, and ignition system were updated. Significant research efforts in Japan, Europe, and the United States are under way to capitalize on the potential offered by diamond's unique material properties, combined with increased quality and quantity of supply starting to become available from synthetic diamond manufacturers.
. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics. There was a further facelift in 1998 and chassis modifications for 2003. With the continuing advances being made in the production of synthetic diamond, future applications are beginning to become feasible.

In 1992, along with dropping the LTD designation, the sedan body (production of the station wagon having ceased in 1991) was completely redesigned to the round, six-window shape (which shared many details with its contemporary, the newly refreshed 1992 Taurus), and there was a new 4.6 L modular engine. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows. It replaced the previous year's LTD Landau model, and used a stainless steel band over the roof at the B-pillar to evoke the 1950s model. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. In 1980, Ford brought back the name on a deluxe version of the LTD full-size car line on the Ford Panther platform. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality except for their small size, can find an industrial use. The model was produced in 1955 and 1956. The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing.

The first "Crown Victoria" appeared in 1955; it was a 2-door 6-seater hardtop coupe, part of the Ford Fairlane range, that differed from the regular Victoria model (named after a type of carriage) by having a stainless steel band that 'crowned' the roofline, passing right over the car, as an extension of the B-pillar line. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 400 million carats (80,000 kg) of synthetic diamonds are produced annually for industrial use—nearly four times the mass of natural diamonds mined over the same period. As of 2005, prices range from $25k for the base model to $32k for the high-end LX Sport trim. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use. Thomas, Ontario, Canada and rides on the 1979 Ford Panther platform and utilizes the universal 4.6L OHC SEFI V8. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. The Crown Victoria is manufactured in St. The market for industrial-grade diamonds operates much differently from its gem-grade counterpart.

Much like its predecessor, the Ford LTD, the Ford Crown Victoria is also commonly used as a taxi cab, fleet vehicle and police car, a segment in which the Crown Victorias makes up the vast majority of vehicles used. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the now-familiar slogan "a diamond is forever". The Crown Victoria, or "Crown Vic" as it is often referred, represents the top-of-the-line sedan in the Ford model line-up. Ayer's multifaceted marketing campaign included product placement, advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. The Ford Crown Victoria is a full-sized sedan manufactured by the Ford Motor Company. N.W. . Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market and opened up new markets, even in countries where no diamond tradition had existed before.

While it shares components with the Lincoln Town Car, it shares almost no exterior sheetmetal or interior parts. N.W. The Grand Marquis is almost never used by fleets other than rental car companies, while it is very popular among the general public. The De Beers diamond advertising campaign is acknowledged as one of the most successful and innovative ones in history. While the Crown Victoria only has mediocre sales to the general public, the Crown Victoria is very popular among fleets, with its twin, the Mercury Grand Marquis being the exact opposite. De Beers has used its monopoly position to establish strict price controls, and aggressively market diamonds directly to consumers in world markets. The Ford Crown Victoria is a fullsize car produced by the Ford Motor Company in the 1950s, and then again in the 1970s. At one time it was thought over 80 percent of the world's rough diamonds passed through the Diamond Trading Company (DTC, a subsidiary of De Beers) in London, but presently the figure is estimated at around 60 percent.

In addition, to go outside that naming scope, reviving the Galaxie nameplate has also been mentioned. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production, and control distribution channels handling nearly two thirds of all gem diamonds. To go with Ford's naming scheme of naming cars that start with the letter "F", the Crown Vic name would be replaced by "Falcon" or "Fairlane". De Beers owns or controls a significant portion of the world's rough diamond production facilities (mines) and distribution channels for gem-quality diamonds. The Panther platform would be retired altogether, replaced by a completely new vehicle based on the Ford D2C platform used for the Ford Mustang. The De Beers company holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888. Despite consumer demand, Ford has no plans to do this. 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).

Ford Australia would modify the Ford Falcon to left hand drive and US safety standards and export it to the US, which would see a revival in the Falcon name in the US market. They are based in Johannesburg, South Africa and London, England. 220 hp L 4.6 L V8. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations (most importantly New York, Antwerp, London, Tel Aviv, Amsterdam and Surat), and a single company—De Beers—controls over half of all trade in diamonds. Unlike precious metals such as gold or platinum, gem diamonds do not trade as a commodity: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. A large trade in gem-grade diamonds exists.

While a large trade in both types of diamonds exists, the two markets act in dramatically different ways. The diamond industry can be broadly separated into two basically distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. The largest flawless and colorless (grade D) diamond is the Millennium Star (1990) at 203.04 carats. One of the diamonds cut from it, Cullinan I or the Great Star of Africa, was formerly the largest cut diamond at 530.2 carats, but now that title has been taken by the Golden Jubilee (1985), a 545.67 carat yellow-brown diamond.

The Cullinan Diamond, owned by Queen Elizabeth II was the largest gem-quality rough diamond ever found (1905), at 3,106.75 carats. A number of large diamonds have become historically significant objects, as their inclusion in various sets of crown jewels and the purchase, sale, and sometimes theft of notable diamonds, have sometimes become politicized. Popularity continued to rise as new cuts were developed that enhanced the diamond's aesthetic appeal, and has largely continued unabated to this day; diamonds have proven popular with all classes in society as their cost has become within reach. However, within a century diamonds were popular gems among the moneyed aristocratic and merchant classes, and by at latest 1477 had begun to be used in wedding rings.

In the 13th century, King Louis IX of France established a law that only the king could own diamonds. The rise in popularity of diamonds as gems seems to have paralleled increasing availability through European history. In 1919, Marcel Tolkowsky developed an ideal round brilliant cut design that has set the standard for comparison of modern gems; however, diamond cuts have continued to be refined. Over the following centuries, various diamond cuts were introduced which increasingly demonstrated the fire and brilliance that makes diamonds treasured today: the table cut, the briolette (around 1476), the rose cut (mid-16th century), and by the mid-17th century, the Mazarin, the first brilliant cut diamond design.

By 1375, a guild of diamond polishers had been established at Nuremberg. During this time, the taboo against cutting diamonds into gem shapes, which was established over 1,000 years earlier in the traditions of India, ended allowing the development of diamond cutting technology to begin in earnest. Around 1300, the flow of diamonds into Europe increased via Venice's trade network, with most flowing through the low country ports of Bruges, Antwerp, and Amsterdam. Until the late Middle Ages, diamonds were most prized in their natural octahedral state, perhaps with the crystal surfaces polished to increase luster and remove foreign material.

In Europe, however, diamonds disappeared for almost 1,000 years following the rise of Christianity because of two effects: early Christians rejected diamonds because of their earlier use in amulets, and Arabic traders restricted the flow of trade between Europe and India. Archeological evidence from Yemen suggests that diamonds were used as drill tips as early as the 4th century BCE. In China, diamonds seem to have been used primarily for engraving jade and drilling holes in beads. The Roman writer Pliny the Elder noted diamond's ornamental uses, as well as its usefulness to engravers because of its hardness, in his work Naturalis Historia.

Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemological or industrial uses. At that scale, the surface of the modern diamond-polished corundum closely resembled that of the axes; however, the polishes of the latter were superior. Although there are diamond deposits now known to exist close to the burial sites, no direct evidence of coeval diamond mining has been found: the researchers came to this conclusion by polishing corundum using various lapidary abrasives and modern techniques then comparing the results using an atomic force microscope. team of archaeologists reported the discovery of four corundum-rich stone ceremonial burial axes originating from China's Liangzhu and Sanxingcun cultures (4000 BCE–2500 BCE) which, because of the axes' specular surfaces, the scientists believe were polished using diamond powder [2] [3].

In February 2005, a joint Chinese-U.S. Ownership was restricted among various castes by color, with only kings being allowed to own all colors of diamond. Diamonds quickly became associated with divinity, being used to decorate religious icons, and were believed to bring good fortune to those who carried them. The earliest written reference can be found in the Sanskrit text Arthasastra, which was completed around 296 BCE, describes diamond's hardness, luster, and dispersion.

Diamonds are thought to have been first recognized and mined in India, where significant alluvial deposits of the stone could then be found. However, cleanliness might reflect a diamond's sentimental value: some jewelers have noted a correlation between ring cleanliness and marriage quality [1]. Cleanliness does not affect the diamond's market value, as any competent jeweler will clean the diamond before offering it for sale. Some jewelers provide their customers with ammonia-based cleaning kits; ultrasonic cleaners are also popular.

Maintaining a clean diamond can sometimes be difficult, as jewelry settings can obstruct cleaning efforts, and oils, grease, and other hydrophobic materials adhere well to a diamond's surface. Current practice is to thoroughly clean a diamond before grading its color. Historically, some jewelers' stones were misgraded because of smudges on the girdle, or dye on the culet. Colored dye or smudges can affect the perceived color of a diamond.

Even a thin film absorbs some light that could have been reflected to the person looking at the diamond. Water, dirt, or grease on the bottom of a diamond interferes with the diamond's brilliance and fire. Dirt or grease on the top of a diamond reduces its luster. A clean diamond is more brilliant and fiery than the same diamond when it is "dirty".

Although it is not one of the four Cs, cleanliness affects a diamond's beauty as much as any of the four Cs. Since the per carat price of diamond shifts around key milestones (such as 1.00 carat), many one-carat diamonds are the result of compromising "Cut" for "Carat." Some jewelry experts advise consumers to buy a 0.99 carat diamond for its better price or buy a 1.10 carat diamond for its better cut, avoiding a 1.00 carat diamond which is more likely to be a poorly cut stone. Sometimes the cutters compromise and accept lesser proportions and symmetry in order to avoid inclusions or to preserve the carat rating. Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%.

Oddly shaped crystals such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. The choice of cut is often decided by the original shape of the rough stone, location of the inclusions and flaws to be eliminated, the preservation of the weight, popularity of certain shapes amongst consumers and many other considerations. The process of shaping a rough diamond into a polished gemstone is both an art and a science.

EightStar Diamond has results of the FireScope. Hearts on Fire Diamond has results of the Hearts and Arrows viewer. Solasfera Diamond has results of Hearts and Arrows viewer, GemEx BrillianceScope, and FireScope. Along with this shift there are a few companies that provide results on these viewers and machines in addition to the original 4c's.

These viewers and machines often help consumers determine the light preformance results of the diamond in addition the the traditional 4 C's. SymmetriScope or IdealScope (tests for light leakage, light return and proportions), Hearts and Arrows Viewer (test for "hearts and arrows" characteristic pattern observable on stones exhibiting high symmetry), GemEx BrillianceScope (tests for direct light performance results of a diamond), Isee2 Machine (tests for diffused light performance results of a diamond), and ASET (test for AGS cut grade). They included the FireScope, a.k.a. A number of specially modified viewers and machines have been developed toward this end.

Recently, there has been a shift away from grading cut by the use of various angles and proportions toward measuring the performance of a cut stone. Several different theories on the "ideal" proportions of a diamond have been and continue to be advocated by professional gemologists. An inferior cut will produce a stone that appears dark at the center and in some extreme cases the ring settings may show through the top of the diamond as shadows. A well executed round brilliant cut should reflect most light out from the tabletop and make the diamond appear white when viewed from the top.

For a round brilliant cut, there is a balance between "brilliance" and "fire." When a diamond is cut for too much "fire," it looks like a cubic zirconia, which gives off much more "fire" than real diamond. A poorly cut diamond with facets cut only a few degrees out of alignment can result in a poorly performing stone. A number of factors, including proportion, symmetry, and the relative angles of various facets, are determined by the quality of the cut and can affect the performance of a diamond. In addition to carrying the most importance to a diamond's quality as a gemstone, the cut is also the most difficult to quantitatively judge.

The skill with which a diamond is cut determines its ability to reflect and refract light. The quality of a diamond's cut is widely considered the most important of the four Cs in determining the beauty of a diamond; indeed, it is commonly acknowledged that a well-cut diamond can appear to be of greater carat weight, and have clarity and color appear to be of better grade than they actually are. These newly developed cuts are viewed by many as more of an attempt at brand differentiation by diamond sellers, than actual improvements to the state of the art. Some of these include extra facets.

The past decades have seen the development of new diamond cuts, often based on a modification of an existing cut. The princess cut is also popular amongst diamond cutters: of all the cuts, it wastes the least of the original crystal. Cuts are influenced heavily by fashion: the baguette cut—which accentuates a diamond's luster and downplays its fire—was all the rage during the Art Deco period, whereas the princess cut—which accentuates a diamond's fire rather than its luster—is currently gaining popularity. Generally speaking, these "fancy cuts" are not held to the same strict standards as Tolkowsky-derived round brilliants and there are less specific mathematical guidelines of angles which determine a well-cut stone.

Diamonds which are not cut to the specifications of Tolkowsky's round brilliant shape (or subsequent variations) are known as "fancy cuts." Popular fancy cuts include the baguette (from the French, resembling a loaf of bread), marquise, princess (square outline), heart, briolette (a form of the rose cut), and pear cuts. Diamonds are cut into a variety of shapes that are generally designed to accentuate these features. Diamonds do not show all of their beauty as rough stones; instead, they must be cut and polished to exhibit the characteristic fire and brilliance that diamond gemstones are known for. Mathematically, the diameter in millimeters of a round brilliant should approximately equal 6.5 times the cube root of carat weight, or 11.1 times the cube root of gram weight.

Typically a round brilliant 1.0 carat diamond should have a diameter of about 6.5 mm. Another quick indication is the overall diameter. "Ideal" round brilliant diamonds should not have a depth percentage greater than 62.5%. The depth percentage is the overall quickest indication of the quality of the cut of a round brilliant.

So a poorly cut 1.0 carat diamond may have the same diameter and appear as large as a 0.85 carat diamond. Neither of the these tactics make the diamond appear any bigger, but it also greatly reduces the sparkle of the diamond. There is a financial premium for a diamond that weighs the magical 1.0 carat, so often the girdle is made thicker or the depth is increased. However, there is a small range in which the diamond can be considered "ideal." Today, because of the relative importance of carat weight in society, many diamonds are often intentionally cut poorly to increase carat weight.

The further the diamond's characteristics are from Tolkowsky's ideal, the less light will be reflected. A normal girdle should be about 1%–2% of the overall diameter. However, a thin girdle is required in reality in order to prevent the diamond from easily chipping in the setting. Tolkowsky's ideal dimensions did not include a girdle.

This should be a negligible diameter, otherwise light leaks out of the bottom. The culet is the tiny point at the bottom of the diamond. Tolkowsky defines the ideal dimensions to have:. The function of the crown is to diffuse light into various colors and the pavilion's function to reflect light back through the top of the diamond.

The girdle is the thin unpolished middle. The modern round brilliant has 57 facets (polished faces), counting 33 on the crown (the top half), and 24 on the pavilion (the lower half). He developed the round brilliant cut by calculating the ideal shape to return and scatter light when a diamond is viewed from above. The techniques for cutting diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in 1919 by mathematician and gem enthusiast Marcel Tolkowsky.

Round brilliant diamonds, the most common, are guided by these specific guidelines, though fancy cut stones are not able to be as accurately guided by mathematical specifics. There are mathematical guidelines for the angles and length ratios at which the diamond is supposed to cut at in order to reflect the maximum amount of light. Often diamond cut is confused with "shape.". The cut of a diamond describes the quality of workmanship and the angles to which a diamond is cut.

The cut of a diamond describes the manner in which a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. Diamond cutting is the art and science of creating a gem-quality diamond out of mined rough. Gemologists have developed rating systems for fancy colored diamonds, but they are not in common use because of the relative rarity of colored diamonds. Intense yellow coloration is considered one of the fancy colors, and is separate from the color grades of white diamonds.

Diamonds with unusual or intense coloration are sometimes labeled "fancy" by the diamond industry. A variety of impurities and structural imperfections cause different colors in diamonds, including yellow, pink, blue, red, green, brown, and other hues. While even a pale pink or blue hue may increase the value of a diamond, more intense coloration is usually considered more desirable and commands the highest prices. In contrast to yellow or brown hues, diamonds of other colors are much rarer and more valuable.

N-Y are usually appear light yellow or brown. Diamonds graded D-F are considered "colorless", G-J are considered "near-colorless", K-M are "slightly colored". Oddly enough, diamonds graded Z are also rare, and the bright yellow color is also highly valued. Diamonds with higher color grades are rarer, in higher demand, and therefore more expensive, than lower color grades.

The system uses a benchmark set of either natural diamonds of known color grade, or precision-crafted cubic zirconia; test lighting conditions are also standardized and carefully controlled. The GIA has developed a rating system for color in white diamonds, from "D" to "Z" (with D being "colorless" and Z having a bright yellow coloration), which has been widely adopted in the industry and is universally recognized, superseding several older systems once used in different countries. This effect is present in almost all white diamonds; in only the rarest diamonds is the coloration due to this effect undetectable. The most common impurity, nitrogen, replaces a small proportion of carbon atoms in a diamond's structure and causes a yellowish to brownish tint.

Most diamonds used as gemstones are basically transparent with little tint, or white diamonds. For example, most white diamonds are discounted in price as more yellow hue is detectable, while intense pink or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice.

However, in reality almost no gem-sized natural diamonds are absolutely perfect. A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. (see the main article for more detail). Diamonds are graded by the major societies on a scale ranging from Flawless to Imperfect.

Large cracks close to or breaking the surface may reduce a diamond's resistance to fracture. However, large clouds can affect a diamond's ability to transmit and scatter light. Most inclusions present in gem-quality diamonds do not affect the diamonds' performance or structural integrity. Those that do not have a visible inclusion are known as "eye-clean" and are preferred by most buyers, although visible inclusions can sometimes be hidden under the setting in a piece of jewelry.

Of that top 20 percent, a significant portion contains an inclusion or inclusions that are visible to the naked eye upon close inspection. Only about 20 percent of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone; the other 80 percent are relegated to industrial use. Diamonds become increasingly rare when considering higher clarity gradings. The Gemological Institute of America (GIA) and others have developed systems to grade clarity, which are generally based on those inclusions which are visible to a trained professional when a diamond is viewed from above, under 10x magnification.

The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. Clarity is a measure of internal defects of a diamond called inclusions. is also widely used for diamond necklaces, bracelets and other similar jewelry pieces.

T.c.w. when placed for sale, indicating the mass of the diamonds in both earrings and not each individual diamond. Diamond solitaire earrings, for example, are usually quoted in t.c.w. Total carat weight (t.c.w.) is a phrase used to describe the total mass of diamonds or other gemstone in a piece of jewelry, when more than one gemstone is used.

Because of this, diamond prices (particularly among wholesalers and other industry professionals) are often quoted per carat, rather than per stone. For example, a buyer may place an order for 100 carats of 0.5 carat, D–F, VS2-SI1, excellent cut diamonds, indicating he wishes to purchase 200 diamonds (100 carats total mass) of those approximate characteristics. In the wholesale trade of gem diamonds, carat is often used in denominating lots of diamonds for sale. Jewelers often trade diamonds at negotiated discounts off the Rapaport price (e.g., "R -3%").

A weekly price list published by Rapaport of New York, of diamond prices per carat, for different diamond cuts, clarity and weights, is currently considered the de-facto retail price baseline. As an example, a 0.95 carat diamond may have a significantly lower price per carat than a comparable 1.05 carat diamond, because of differences in demand. Instead, there are sharp jumps around milestone carat weights, as demand is much higher for diamonds weighing just more than a milestone than for those weighing just less. The price per carat does not increase smoothly with increasing size.

A review of comparable diamonds available for purchase in September 2005 demonstrates this effect (approximate prices for round cut, G color, VS2 diamonds with "1A" cut grade, as listed on http://www.pricescope.com):. All else being equal, the value of a diamond increases exponentially in relation to carat weight, since larger diamonds are both rarer and more desirable for use as gemstones. The point unit—equal to one one-hundredth of a carat (0.01 carat, or 2 mg)—is commonly used for diamonds of less than one carat. One carat is defined as exactly 200 milligrams (about 0.007 ounce).

The carat weight measures the mass of a diamond. While carat weight and cut angles are mathematically defined, the clarity and color are judged by the trained human eye and are therefore open to slight variance in interpretation. There are four major gemological associations which "certify" diamonds: that is, define the four Cs of a diamond. Cleanliness also dramatically affects a diamond's beauty.

These characteristics include physical characteristics such as the presence of fluorescence, as well as data on a diamond's history including its source and which gemological institute performed evaluation services on the diamond. Other characteristics not described by the four Cs can and do influence the value or appearance of a gem diamond. Consumers who purchase individual diamonds are often advised to use the four Cs to pick the diamond that is "right" for them; to these is sometimes added the "fifth C" of cost. More detailed information from within each characteristic can then be used to determine actual market value for individual stones.

Most gem diamonds are traded on the wholesale market based on single values for each of the four Cs; for example knowing that a diamond is rated as 1.5 carats, VS2 clarity, F color, excellent cut, is enough to reasonably establish an expected price range. Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds: these are carat, clarity, color, and cut. Over time, especially since around 1900, experts in the field of gemology have developed methods of characterizing diamonds and other gemstones based on the characteristics most important to their value as a gem. The dispersion of white light into a rainbow of colors, known in the trade as fire, is the other primary characteristic of gem diamonds, and has been highly prized throughout history.

The use of diamonds as gemstones of decorative value is the most familiar use to most people today, and is also the earliest use, with decorative use of diamonds stretching back into antiquity. Diamonds can also be brought to the surface through certain processes which may occur when two continental plates collide forcefully, although this phenomenon is less understood and currently assumed to be uncommon. Diamonds have also rarely been found in deposits left behind by glaciers (notably in Wisconsin and Indiana); however, in contrast to alluvial deposits, glacial deposits are not known to be of significant concentration and are therefore not viable commercial sources of diamond. These include alluvial deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their approximate size and density.

Secondary sources of diamonds include all areas where a significant number of diamonds, eroded out of their kimberlite or lamproite matrix, accumulate because of water or weather action. A volcanic pipe containing diamonds is known as a primary source of diamonds. Once diamonds have been forced to the surface by magma in a volcanic pipe, they may erode out and be distributed over a large area. 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.

The most common indicator minerals are chromian garnets (usually bright red Cr-pyrope, and occasionally green ugrandite-series garnets), eclogitic garnets, orange Ti-pyrope, red high chromian spinels, dark chromite, bright green Cr-diopside, glassy green olivine, black picroilmenite, and magnetite. These minerals are rich in chromium (Cr) or titanium (Ti), elements which impart bright colors to the minerals. Certain indicator minerals typically occur within diamondiferous kimberlites and are used as mineralogic tracers in the search for diamond deposits by prospectors. These rocks are characteristically rich in magnesium bearing olivine, pyroxene, and amphibole minerals which are usually altered to serpentine under near surface conditions.

The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks and material upward. The magma in such volcanic pipes is usually one of two characteristic types, which cool into igneous rock known as either kimberlite or lamproite. Diamond-bearing volcanic pipes are most commonly found in the oldest regions of continental crust, which relates to the fact that these areas are the coolest portions of the earth's crust, and therefore diamonds can form at the shallowest depths. Below these typically small surface volcanic craters are formations known as volcanic pipes, which contain material that was pushed toward the surface of the earth by volcanic action, but did not erupt before the volcanic activity ceased.

The magma for such a volcano must originate at a depth where diamonds can be formed, 90 miles (150 km) deep or more (three times or more the depth of source magma for most volcanoes); this is a relatively rare occurrence. Diamond-bearing rock is forced close to the surface through deep-origin volcanic eruptions. Microdiamonds are now used as one indicator of ancient meteorite impact sites. Very small diamonds, known as microdiamonds or nanodiamonds, have been found in impact craters where meteors strike the Earth and create shock zones of high pressure and temperature where diamond formation can occur.

Diamonds can also form in other natural high-pressure, high-temperature events. Diamonds (especially those from secondary deposits) are commonly found coated in nyf, an opaque gum-like skin. This is all due to the conditions in which they form. Sometimes they are found grown together or form double "twinned" crystals grown together at the surfaces of the octahedron.

The crystals can have rounded off and unexpressive edges and can be elongated. 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. Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3.3 billion years old.

These two different source carbons have measurably different ¹³C:¹²C ratios. 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. Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. Through studies of carbon isotope ratios (similar to the methodology used in carbon dating) except using 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.

Long periods of exposure to these high pressures and temperatures allow diamond crystals to grow larger. Diamond formation under oceanic crust takes place at greater depths because of higher temperatures, which require higher pressure for diamond formation. Under continental crust, diamonds form starting at depths of about 150 kilometers (90 miles), where pressure is roughly 5 gigapascals and the temperature is around 1200 degrees Celsius (2200 degrees Fahrenheit). On Earth, the formation of diamonds is possible because there are regions deep within the Earth that are at a high enough pressure and temperature that the formation of diamonds is thermodynamically favorable (see the diamond phase diagram and geotherms here).

Diamond is formed by prolonged exposure of carbon bearing materials to high pressure and temperature.
. Because diamond has such high thermal conductance it is already used in semiconductor manufacture to prevent silicon and other semiconducting materials from overheating. Specially purified synthetic diamond has the highest thermal conductivity (2000–2500 W/(m·K), five times more than copper) of any known solid at room temperature.

Most natural blue diamonds contain boron atoms which replace carbon atoms in the crystal matrix, and also have high thermal conductivity. Unlike most electrical insulators, diamond is a good conductor of heat because of the strong covalent bonding within the crystal. Blue diamonds which are not boron-doped, such as those recently recovered from the Argyle diamond mine in Australia that owe their color to an overabundance of hydrogen atoms, are not semiconductors. Blue diamonds owe their semiconductive property to boron impurities, which act as a doping agent and cause p-type semiconductor behavior.

Except for most blue diamonds, which are semiconductors, diamonds are good electrical insulators. Most diamonds show no fluorescence although colored diamonds show a wider range of fluorescence than the blue fluorescence normally observed in clear diamonds. Nearly all diamonds fluoresce bluish-white, yellow or green under X-rays and this property is used extensively in mining to separate the fluorescing diamond from the non-fluorescing rock. Some diamonds exhibit fluorescence of various colors (predominately blue) under long wave ultraviolet light.

This is owed to their high refractive index of 2.417 (at 589.3 nm), which causes total internal reflection to occur. The luster of a diamond, a characterization of how light interacts with the surface of a crystal, is brilliant and is described as adamantine, which simply means diamond-like. This strong ability to split white light into its component colors is an important aspect of diamond's attraction as a gemstone, giving it impressive prismatic action that results in so-called fire in a well-cut stone. Diamonds exhibit a high dispersion of visible light.

However, owing to a very large kinetic energy barrier, diamonds are metastable; under normal conditions, it would take an extremely long time (possibly more than the age of the Universe) for diamond to decay into graphite. This was shown in the late 18th century, and previously described during Roman times. Diamonds will burn at approximately 800 degrees Celsius, providing that enough oxygen is available. At surface air pressure (one atmosphere), diamonds are not as stable as graphite, and so the decay of diamond is thermodynamically favorable (ΔG = −2.99 kJ / mol).

The most common impurity, nitrogen, causes a yellowish or brownish tinge. Most diamond impurities replace a carbon atom in the crystal lattice. Colored diamonds contain impurities or structural defects that cause the coloration, while pure or nearly pure diamonds are transparent and colorless. Diamonds with a detectable hue to them are known as colored diamonds.

Diamonds occur in a variety of transparent hues — colorless, white, steel, blue, yellow, orange, red, green, pink, brown—or colored black. Diamonds cut into certain particular shapes are therefore more prone to breakage than others. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Toughness relates to a material's ability to resist breakage from forceful impact.

Unlike hardness, which only denotes resistance to scratching, diamond's toughness is only fair to good. 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 an engagement ring or wedding ring, which are often worn every day. Because it can only be scratched by other diamonds, it maintains its polish extremely well, keeping its luster over long periods of time. The hardness of diamonds also contributes to its suitability as a gemstone.

Industrial applications, especially as drill bits and engraving tools, also date to ancient times. Industrial-grade diamonds are either unsuitable for use as gems or synthetically produced, which lowers their price and makes their use economically feasible. Other specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most other diamonds, which are excellent electrical insulators. Common industrial adaptations of this ability include diamond-tipped drill bits and saws, or use of diamond powder as an abrasive.

As the hardest known naturally occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. It is one of the most known and most useful of more than 3,000 known minerals. Industrial use of diamonds has historically been associated with their hardness; this property makes diamond the ideal material for cutting and grinding tools. 1990).

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 (Taylor et al. Their hardness is considered to be a product of the crystal growth form, which is single stage growth crystal. These diamonds are generally small, perfect to semiperfect octahedra and are used to polish other diamonds. The hardest diamonds in the world are diamonds from the New England area in New South Wales, Australia.

However, aggregated diamond nanorods, an allotrope of carbon first synthesized in 2005, are now believed to be even harder than diamond. Diamond's hardness has been known since antiquity, and is the source of its name. Diamond is the hardest known naturally occurring material, scoring 10 on the relative Mohs scale of mineral hardness and having an absolute hardness value of between 167 and 231 gigapascals in various tests. A colorless, grey or black diamond with a tiny radial structure is a spherulite.

A cryptocrystalline variety of diamond is called carbonado. Lonsdaleite is a polymorph of diamond (and a distinct mineral species) that crystallizes with hexagonal symmetry; it is rarely found in nature, but is characteristic of synthetic diamonds. Other elements of the carbon group such as silicon have forms analogous to diamond. Graphite, another allotrope of carbon, has a rhombohedral crystal structure and as a result shows dramatically different physical characteristics — contrary to diamond, graphite is a very soft, dark grey, opaque mineral.

The tetrahedral arrangement of atoms in a diamond crystal is the source of many of diamond's properties. The unit cell of diamond has a two atom basis at (0,0,0) and (1/4,1/4,1/4), which means half of the atoms are at lattice points and the other half are offset by (1/4,1/4,1/4), where 1 is the length of a side of the unit cell. Diamonds typically crystallize in the face-centered cubic crystal system and consist of tetrahedrally bonded carbon atoms. These properties form the basis for most modern applications of diamond.

Most notable among these properties are the extreme hardness of diamond, its high dispersion index, and high thermal conductivity. Humans have been able to adapt diamonds for many uses because of the material's exceptional physical characteristics. Diamond is a transparent crystal of pure carbon consisting of tetrahedrally bonded carbon atoms. See also: Crystallographic defects in diamond.

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. There are also allegations that the De Beers Group misuses its dominance in the industry to control supply and manipulate price via monopolistic practices. The mining and distribution of natural diamonds are subjects of frequent controversy—such as with concerns over the sale of conflict diamonds by African paramilitary groups.

They are generally mined from volcanic pipes, which are deep in the Earth where the high pressure and temperature enables the formation of the crystals. Most natural diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, Russia, Brazil, and Australia. Although nearly four times the mass of natural diamonds are produced as synthetic diamond each year, the vast majority of synthetic diamond production remains small, imperfect diamonds suitable only for industrial-grade use, with gem-quality synthetic diamonds only recently becoming available. Popularity of diamonds has risen since the 19th century because of improved cutting and polishing techniques, and they are commonly judged by the "four Cs": carat, clarity, color, and cut.

They have been treasured as gems since their use as religious icons in India at least 2,500 years ago—and usage in drill bits and engraving tools also dates to early human history. The name "diamond" derives from the ancient Greek adamas (αδάμας; "impossible to tame"). About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion. Diamonds are specifically renowned as a mineral with superlative physical qualities - they make excellent abrasives because they can only be scratched by other diamonds, which also means they hold a polish extremely well and retain luster.

Diamond is one of the two best known forms (or allotropes) of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry (the other equally well known allotrope is graphite). Crown Depth (Depth of crown divided by crown diameter) = 16.2%. Pavilion Depth (Depth of pavilion divided by overall diameter) = 43.1%. Crown Angle (Angle between the girdle and the crown) = 34.5°.

Pavilion Angle (Angle between the girdle and the pavilion) = 40.75°. Depth percentage (Overall depth divided by the overall diameter) = 59.3%. Table percentage (table diameter divided by overall diameter) = 53%. European Gemological Laboratory (EGI) has a similar reputation to the IGL.

International Gemological Laboratory (IGL) is a generally respected laboratory but suffers from a negative industry reputation for its grading practices, which are perceived by critics as being either less conservative or less consistent than the GIA and AGS. American Gemological Society (AGS) is not as widely recognized nor as old as the GIA, but garners an equally high reputation. Gemological Institute of America (GIA) was the first laboratory to issue modern diamond reports, and holds the highest reputation amongst gemologists for its consistent, conservative grading.