हेरा: Difference between revisions
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Eukesh (खँल्हाबल्हा | योगदान) No edit summary |
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{{अनुवाद}}
{{Infobox mineral
| name = हेरा
| category = Native Minerals
| boxwidth =
| boxbgcolor =
| image = Brillanten.jpg
| imagesize = 300 <!-- this value is in px -->
| caption = A scattering of round-brilliant cut diamonds shows off the many reflecting facets.
| formula = C
| molweight = 12.01 u
| color = Typically yellow, brown or gray to colorless. Less often in blue, green, black, translucent white, pink, violet, orange, purple and red.<ref name="GRG"/>
| habit = [[अक्टाहेड्रल]]
| system = आइसोमेट्रिक-हेक्साक्टाहेड्रल (क्युबिक)
| twinning =
| cleavage = १११ (perfect in four directions)
| fracture = [[कङ्कोइडल]] - स्वाने थें
| tenacity =
| mohs = १०<ref name="GRG"/>
| luster = [[Adamantine]]<ref name="GRG"/>
| polish = [[Adamantine]]<ref name="GRG">[[Gemological Institute of America]], ''GIA Gem Reference Guide'' 1995, ISBN 0-87311-019-6</ref>
| refractive = 2.4175–2.4178
| opticalprop = Singly Refractive<ref name="GRG"/>
| birefringence = none<ref name="GRG"/>
| dispersion = .044<ref name="GRG"/>
| pleochroism = none<ref name="GRG"/>
| fluorescence= colorless to yellowish stones - inert to strong in long wave, and typically blue. Weaker in short wave.<ref name="GRG"/>
| absorption = In pale yellow stones a 415.5 nm line is typical. Irradiated and annealed diamonds often show a line around 594 nm when cooled to low temperatures.<ref name="GRG"/>
| streak = White
| gravity = 3.52 (+/- .01)<ref name="GRG"/>
| density = 3.5-3.53 g/cm³
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity = Transparent to subtransparent to translucent
| other =
}}
<!--First paragraph Chemistry and Material Properties, Industry Size-->
'''हेरा''' [[कार्बोन]]यागु छगु रुप खः। थुकिलि कार्बोनयागु सकल प्येंगु भ्यालेन्ट [[एलेक्ट्रोन]] [[को-भ्यालेन्ट बन्ड]] देका च्वनि।
In [[mineralogy]], '''diamond''' is the [[Allotropes of carbon|allotrope of carbon]] where the carbon atoms are arranged in an isometric-hexoctahedral crystal lattice. Its hardness and high [[Dispersion (optics)|dispersion]] of [[light]] make it useful for industrial applications and [[jewelry]]. It is the [[hardness|hardest]] known naturally-occurring [[mineral]]. It is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds (known as Type-II diamonds) that are harder than the diamonds used in hardness gauges.<ref name="Smithsonian">{{cite journal | author = Boser, Ulrich |month = June | year = 2008 | title = Diamonds on Demand | journal = Smithsonian | volume = 39 | issue = 3 | pages = 52–59 }}</ref> Presently, only [[aggregated diamond nanorods]], a material created using [[ultrahard fullerite]] (C<sub>60</sub>) is confirmed to be harder, although other substances such as [[cubic boron nitride]], [[rhenium diboride]] and [[ultrahard fullerite]] itself are comparable.
Diamonds are specifically renowned as a material with superlative physical qualities; they make excellent [[abrasive]]s because they can be scratched only by other diamonds, [[borazon]], ultrahard fullerite, rhenium diboride, or aggregated diamond [[nanorods]], which also means they hold a polish extremely well and retain their [[Lustre (mineralogy)|lustre]]. Approximately 130 million [[Carat (mass)|carats]] ({{convert|26000|kg|abbr=on}}) are mined annually, with a total value of nearly [[US dollar|USD $]]9 [[1000000000 (number)|billion]], and about {{convert|100000|kg|abbr=on}} are synthesized annually.<ref>{{cite journal|last = Yarnell|first=Amanda|title=The Many Facets of Man-Made Diamonds|journal=Chemical and Engineering News|volume=82|issue=5|pages=26–31|publisher=American Chemical Society|year=2004|url=http://pubs.acs.org/cen/coverstory/8205/8205diamonds.html|id =ISSN 0009-2347|accessdate=2006-10-03 }}</ref>
<!--Second paragraph: Etymology and Applications-->
The name ''diamond'' derives from the [[Greek language|ancient Greek]] ''ἀδάμας'' (''adamas'') "invincible", "untamed", from ''ἀ-'' (''a-''), "un-" + ''δαμάω'' (''damáō''), "to overpower, to tame". They have been treasured as [[gemstone]]s since their use as [[icon|religious icons]] in [[Kingdoms of Ancient India|ancient India]] and usage in [[engraving]] tools also dates to early [[History of the world|human history]].<ref>{{cite book |title = Natural History: A Selection | author = [[Pliny the Elder]] | publisher = Penguin Classics | pages = p. 371 | isbn = 0140444130}}</ref><ref name=ancient_China>{{cite news | url = http://news.bbc.co.uk/2/hi/science/nature/4555235.stm | title = Chinese made first use of diamond | publisher = BBC News | date= 2005-05-17 | accessdate = 2007-03-21}}</ref> 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. They are commonly judged by the “four Cs”: ''carat'', ''clarity'', ''color'', and ''cut''.
<!--Third paragraph: Mining and Distribution-->
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. They are mined from [[kimberlite]] and [[lamproite]] [[volcanic pipe]]s, 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 with concerns over the sale of ''[[conflict diamond]]s'' (aka ''blood diamonds'') by African [[paramilitary]] groups.
==Material properties==
{{main|Material properties of diamond}}
{{seealso|Crystallographic defects in diamond}}
[[Image:Diamond and graphite.jpg|thumb|Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.]]
A diamond is a [[transparency (optics)|transparent]] [[crystal]] of [[Tetrahedral-octahedral honeycomb|tetrahedrally]] bonded carbon atoms and crystallizes into the [[face centered cubic]] [[Diamond cubic|diamond lattice]] structure. Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Most notable are its extreme hardness, its high [[dispersion (optics)|dispersion]] index, and extremely high [[thermal conductivity]] (900 – 2320 W/m K). Above 1700 °C (1973 K / 3583 °F), diamond is converted to [[graphite]]<ref>{{cite book |author=Radovic, Ljubisa R.; Walker, Philip M.; Thrower, Peter A. |title=Chemistry and physics of carbon: a series of advances |publisher=Marcel Dekker |location=New York, N.Y |year=1965 |pages= |isbn=0-8247-0987-X |oclc= |doi= |accessdate=}}</ref>. Naturally occurring diamonds have a density ranging from 3.15 to 3.53 g/cm³, with very pure diamond typically extremely close to 3.52 g/cm³.
====Hardness====
Diamond is the hardest natural material known; hardness is defined as resistance to scratching.<ref>{{cite web|url= http://www.gemcutters.org/LDA/hardness.htm|year= 1998 |accessdate=2007-08-19 | title= "The Hardness of Minerals and Rocks" by William S. Cordua|work= Lapidary Digest}} Hosted at [http://www.gemcutters.org/ International Lapidary Association]</ref> Diamond has a hardness of 10 (hardest) on [[Mohs scale of mineral hardness]].<ref name="AMNH">American Museum of Natural History> [http://amnh.org/exhibitions/diamonds/ "The Nature of Diamonds"] Retrieved March 9, 2005</ref> Diamond's hardness has been known since antiquity, and is the source of its name.
The hardest diamonds in the world are from the [[New England (Australia)|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 considered to be a product of the [[crystal growth]] form, which is single stage growth crystal. 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.<ref name="Taylor">{{cite journal | author = Taylor, W.R., Lynton A.J. & Ridd, M. | year = 1990| url = http://www.minsocam.org/ammin/AM75/AM75_1290.pdf | title = Nitrogen defect aggregation of some Australasian diamonds: Time-temperature constraints on the source regions of pipe and alluvial diamonds | format = PDF | journal = American Mineralogist | volume = 75 | pages =pp. 1290–1310}}</ref>
The hardness of diamonds 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 an [[engagement ring|engagement]] or [[wedding ring]]s, which are often worn every day.
Industrial use of diamonds has historically been associated with their hardness; this property 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. However, diamond is a poor choice for machining ferrous alloys at high speeds. At the high temperatures created by high speed machining, carbon is soluble in iron, leading to greatly increased wear on diamond tools as compared to other alternatives. Common industrial adaptations of this ability include diamond-tipped [[drill bit]]s and saws, or use of diamond powder as an [[abrasive]]. Industrial-grade diamonds are generally considered unsuitable for use as gems.
====Electrical conductivity====
Other specialized applications also exist or are being developed, including use as [[semiconductor]]s: some blue diamonds are natural semiconductors, in contrast to most other diamonds, which are excellent electrical [[Electrical insulation|insulator]]s.<ref name="AMNH"/> However, substantial conductivity has been observed for undoped diamond when exposed to air.<ref name="Landstrass">{{cite journal | author = Landstrass, M.I., Ravi, K.V. | year = 1989| journal = Applied Physics Letters | volume = 55 | pages =p. 975
| doi = 10.1063/1.101694
| title = Resistivity of chemical vapor deposited diamond films}}</ref>
====Toughness====
Toughness relates to a material's ability to resist breakage from forceful impact. The [[toughness]] of natural diamond has been measured as 3.4 MN m<sup>-3/2</sup>,<ref>{{cite journal| last = Field| first=J E| title=Strength and Fracture Properties of Diamond| journal=Philosophical Magazine A| volume=43 |issue=3| pages=595–618 |publisher=Taylor and Francis Ltd|year=1981| doi=10.1080/01418618108240397 }}</ref> which is good compared to other gemstones, but poor compared to most engineering materials. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond is therefore more fragile in some orientations than others.
====Color====
{{main|Diamond color}}
Gem quality diamond may be colorless or occur in any hue including the non-spectral hues of gray, brown and black. Diamond is the only gemstone composed of a single element, carbon. The diamond crystal lattice is exceptionally strong and only three atoms; Nitrogen, Boron and Hydrogen are small enough to work their way into the tetrahedral arrangement that is the basic unit of the diamond crystal.
Nitrogen is the smallest and by far the most common impurity found in gem diamonds. Nitrogen is responsible for the yellow, brown and sometimes the pink color in diamonds. Boron is responsible for the gray blue colors and Hydrogen is the coloring agent for some red, olive, violet and blue diamonds. Color in diamond has two additional sources: atomic, normally gamma radiation, that causes the color in green diamonds and physical deformation of the diamond crystal known as plastic deformation. Plastic deformation is the cause of color in some pink and in red diamonds. <ref>Wise, R. W., Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones, 2001, Brunswick House Press. pp. 223-224</ref>. In order of rarity, colorless diamond, by far the most common, is followed by Among the colored diamonds, in blue, green, black, translucent white, pink, violet, orange, purple and red, though yellow and brown are by far the most common colors.<ref name="AMNH"/> "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.<ref name="AMNH"/> 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).
In October 2007 a blue diamond fetched nearly $8 million. The blue hue was a result of trace amounts of boron in the stone's crystal structure.<ref>[http://news.yahoo.com/s/nm/20071008/od_uk_nm/oukoe_uk_hongkong_diamond Rare blue diamond breaks world record in HK sale], YAHOO! News</ref>
====Identification====
Diamonds can be identified by their high thermal conductivity. Their high [[refractive index]] is also indicative, but other materials have similar refractivity. Diamonds do cut glass, but other materials above glass on [[Mohs scale]] such as quartz do also. Diamonds easily scratch other diamonds, but this damages both diamonds.<ref>[http://krampf.com/experiments/Science_Experiment22.html Science Experiment22]</ref>
==Natural history==
===Formation===
The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high [[pressure]], ranging approximately between 45 and 60 [[Bar (unit)|kilobar]]s,<ref name="GIAGrading4">''Diamonds and Diamond Grading: Lesson 4 How Diamonds Form.'' Gemological Institute of America,, Carlsbad, California., 2002</ref> but at a comparatively low [[temperature]] range between approximately 1652–2372 °F (900–1300 °C).<ref name="GIAGrading4"/> These conditions are known to be met in two places on Earth; in the [[Lithosphere|lithospheric mantle]] below relatively stable [[continental plate]]s, and at the site of a [[meteorite]] strike.
====Diamonds formed in cratons====
The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140–190 kilometers (90–120 miles)<ref name="GIAGrading4"/><ref name="AMNH"/> though occasionally diamonds have crystallized at depths of 300-400 km (180-250 miles) as well.<ref name=Sevdermish>{{cite book | last = M. Sevdermish and A. Mashiah | title = The Dealer's Book of Gems and Diamonds | publisher = Kal Printing House, Israel | year = 1995}}</ref> The rate at which [[geothermal gradient|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.<ref name="GIAGrading4"/> The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of [[continental plate]]s where regions of lithosphere known as ''[[craton]]s'' exist.<ref name="GIAGrading4"/> Long residence in the cratonic lithosphere allows diamond crystals to grow larger.
[[Image:Rough diamond.jpg|left|thumb|250px|The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.]]
Through studies of carbon [[isotope]] ratios (similar to the methodology used in [[carbon dating]], except with the [[stable isotope]]s 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 [[Peridotite|''harzburgitic'']], are formed from inorganic carbon originally found deep in the Earth's [[Mantle (geology)|mantle]]. In contrast, [[eclogite|''eclogitic'']] diamonds contain organic carbon from organic [[detritus]] that has been pushed down from the surface of the Earth's [[crust (geology)|crust]] through [[subduction]] (see [[plate tectonics]]) before transforming into diamond.<ref name="AMNH"/> These two different source carbons have measurably different <sup>13</sup>C:<sup>12</sup>C ratios. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 [[1000000000 (number)|billion]] to 3.3 billion years old.
Diamonds occur most often as [[euhedral]] or rounded [[octahedron|octahedra]] and [[Crystal twinning|twinned]] octahedra known as ''macles'' or ''maccles''. As diamond's crystal structure has a cubic arrangement of the atoms, they have many [[facet]]s that belong to a [[Cube (geometry)|cube]], [[octahedron]], [[rhombicosidodecahedron]], [[tetrakis hexahedron]] or [[disdyakis dodecahedron]]. The crystals can have rounded off and unexpressive edges and can be elongated. Sometimes they are found grown together or form double "twinned" crystals grown together at the surfaces of the octahedron. These different shapes and habits of the diamonds result from differing external circumstances. Diamonds (especially those with rounded crystal faces) are commonly found coated in ''nyf'', an opaque gum-like skin.<ref>Webster, Robert, and Read, Peter G. (Ed.) (2000). ''Gems: Their sources, descriptions and identification'' (5th ed.), p. 17. Butterworth-Heinemann, Great Britain. ISBN 0-7506-1674-1.</ref>
====Diamonds and meteorite impact craters====
Diamonds can also form in other natural high-pressure events. Very small diamonds, known as ''microdiamonds'' or ''nanodiamonds'', have been found in [[meteorite]] [[impact crater]]s. Such [[impact events]] create shock zones of high pressure and temperature suitable for diamond formation. Impact-type microdiamonds can be used as one indicator of ancient impact craters.<ref name="AMNH" />
====Extraterrestrial diamonds====
Not all diamonds found on earth originated here. A type of diamond called [[carbonado]] diamond 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.<ref name=Garai2006>{{cite journal | author = Garai, J. | coauthors = Haggerty, S.E.; Rekhi, S.; Chance, M. | year = 2006 | title = Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado Diamonds | journal = The Astrophysical Journal | volume = 653 | issue = 2 | pages = L153–L156 | doi = 10.1086/510451 }}</ref><ref name=Carbonardo>{{cite web | url = http://www.nsf.gov/news/news_summ.jsp?cntn_id=108270&org=NSF | title = Diamonds from Outer Space: Geologists Discover Origin of Earth's Mysterious Black Diamonds | publisher = National Science Foundation | date= 2007-01-08 | accessdate = 2007-10-28}}</ref> These diamonds may have formed in the intrastellar environment, but as of 2008, there was no scientific consensus on how [[carbonado]] diamonds originated.
[[Presolar grains]] in many meteorites found on earth contain nanodiamonds of extraterrestrial origin, probably formed in [[supernova]]s.
Scientific evidence indicates that [[white dwarf]] [[star]]s 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 away in the [[constellation]] [[Centaurus]]. A news release from the [[Harvard-Smithsonian Center for Astrophysics]] described the 2,500 mile-wide stellar core as a ''diamond''.<ref>http://cfa-www.harvard.edu/press/archive/pr0407.html Press release</ref> It is estimated to be ten billion trillion trillion carats, more or less. It was referred to as ''Lucy'', for the Beatle's song "Lucy in the Sky With Diamonds".<ref>{{cite web |url=http://www.theage.com.au/articles/2004/02/17/1076779973101.html |title=Biggest Diamond Out of This World |accessdate=November 11 |accessyear=2007 |last=Cauchi |first=Stephen |date=2004-02-18|year=2004 |month=February}}</ref><ref name="Smithsonian" />
===Surfacing===
[[Image:VolcanicPipe.jpg|right|thumb|float|220px|Schematic diagram of a volcanic pipe]]
Diamond-bearing rock is brought close to the surface through deep-origin [[volcano|volcanic]] eruptions. The [[magma]] for such a volcano must originate at a depth where diamonds can be formed,<ref name="AMNH"/> 150 km (90 miles) deep 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 pipe]]s.<ref name="AMNH"/> 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 [[xenolith]]s of surface rock and even wood and/or [[fossil]]s are found in volcanic pipes. Diamond-bearing volcanic pipes are closely related to the oldest, coolest regions of [[continental crust]] ([[craton]]s). This is because cratons are very thick, and their [[lithosphere|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.
The magma in volcanic pipes is usually one of two characteristic types, which cool into [[igneous rock]] known as either [[kimberlite]] or [[lamproite]].<ref name="AMNH"/> The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks (xenoliths), minerals ([[xenocryst]]s), and fluids upward. These rocks are characteristically rich in [[magnesium]]-bearing [[olivine]], [[pyroxene]], and [[amphibole]] minerals<ref name="AMNH"/> which are often altered to [[serpentine]] by heat and fluids during and after eruption. Certain ''indicator minerals'' typically occur within diamondiferous kimberlites and are used as mineralogic 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 chromian [[garnet]]s (usually bright red Cr-[[pyrope]], and occasionally green ugrandite-series garnets), eclogitic garnets, orange Ti-pyrope, red high-Cr [[spinel]]s, dark [[chromite]], bright green Cr-[[diopside]], glassy green [[olivine]], black [[ilmenite|picroilmenite]], and [[magnetite]].<ref name="AMNH"/> 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 [[weathering|weathered]] and [[oxidation|oxidized]] portion.
Once diamonds have been transported to the surface by magma in a volcanic pipe, they may [[erosion|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, eroded out of their kimberlite or lamproite matrix, accumulate because of water or wind action. These include [[alluvium|alluvial]] deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their approximate size and density. Diamonds have also rarely been found in deposits left behind by glaciers (notably in [[Wisconsin]] and [[Indiana]]); however, in contrast to [[alluvial deposit]]s, glacial deposits are not known to be of significant concentration and are therefore not viable commercial sources of diamond.
== History and gemological characteristics ==
{{main|Diamond (gemstone)}}
Diamonds are thought to have been first recognized and mined in India ([[Golkonda|Golconda]] being one of them), where significant alluvial deposits of the stone could then be found along the rivers Penner, Krishna and Godavari. Diamonds have been known in India for at least 3000 years but most likely 6000 years.<ref name=hershey>{{cite book | last = Hershey MS PhD | first = Willard | title = The Book of Diamonds | publisher = Hearthside Press New York | year = 1940}}</ref> In 1813, [[Humphry Davy]] 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.<ref>{{cite book |author=Thomas, J. M. Lloyd |title=Michael Faraday and the Royal Institution (the genius of man and place) |publisher=A. Hilger |location=Bristol |year=1991 |pages= |isbn=0-7503-0145-7 |oclc= |doi= |accessdate=}}</ref> Later, he showed that in an atmosphere devoid of oxygen, diamond is converted to [[graphite]].
The most familiar usage of diamonds today is as gemstones used for [[adornment]] a usage which dates back into antiquity. The [[dispersion]] of white light into [[spectral color]]s, is the primary gemological characteristic of gem diamonds. In the twentieth century, experts in the field of ''[[gemology]]'' have 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'', ''cut'', ''color'', and ''clarity''.
==The diamond industry==
{{See also|Diamonds as an investment}}
[[Image:Diamond.jpg|framed|A round [[Brilliant (diamond cut)|brilliant cut]] diamond set in a ring]]
The diamond industry can be broadly separated into two basically distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. While a large trade in both types of diamonds exists, the two markets act in dramatically different ways.
===Gem diamond industry===
{{main|Diamond (gemstone)}}
A large trade in [[Gemstone|gem]]-grade diamonds exists. Unlike [[precious metal]]s 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. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and [[diamond cutting]] is limited to a few locations. 92% of diamond pieces cut in 2003 were in [[Surat]], [[Gujarat]], India.<ref>[http://www.time.com/time/magazine/article/0,9171,501040419-610100,00.html Uncommon Brilliance - TIME<!-- Bot generated title -->]</ref> Other important centers of diamond cutting and trading are [[Antwerp]], where the [[International Gemological Institute]] is based, [[London]], [[New York City|New York]], [[Tel Aviv]], [[Amsterdam]]. A single company—[[De Beers]]—controls a significant proportion of the trade in diamonds. They are based in [[Johannesburg]], South Africa and [[London]], England.
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.{{Fact|date=November 2007}} This makes Antwerp the de facto 'world diamond capital'. [[New York]], however, along with the rest of the United States, is where almost 80% of the world's diamonds are sold, including auction sales. Also, the largest and most unusually shaped rough diamonds end up in New York. The De Beers company, as the world's largest diamond miner holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888 by the British imperialist [[Cecil Rhodes]]. De Beers owns or controls a significant portion of the world's rough diamond production facilities ([[mining|mines]]) and [[Distribution (business)|distribution channels]] for gem-quality diamonds. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production. 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 less than 50 percent.
The [[De Beers#Marketing|De Beers diamond advertising campaign]] is acknowledged as one of the most successful and innovative campaigns in history. [[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. N.W. 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. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the [[slogan]] "a diamond is forever".
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 centres such as Tel Aviv, Antwerp, Johannesburg and other cities across the USA, Europe and Asia.
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 also include sponsoring the [[World Diamond Congress]] every two years, as well as the establishment of the ''[[International Diamond Council]]'' (IDC) to oversee diamond grading.
===Industrial diamond industry===
The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. 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. 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. In addition to mined diamonds, [[synthetic diamond]]s found industrial applications almost immediately after their invention in the 1950s; another 3 billion carats (600 [[Tonne|metric tons]]) of synthetic diamond is produced annually for industrial use.
The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. 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. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for [[Pressure experiment|high pressure experiments]] (see [[diamond anvil cell]]), high-performance [[bearing (mechanical)|bearings]], and limited use in specialized [[window]]s.
With the continuing advances being made in the production of synthetic diamonds, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a [[semiconductor]] suitable to build [[integrated circuit|microchip]]s from, or the use of diamond as a [[heat sink]] in [[electronics]].
===Diamond supply chain===
{{See also|List of diamond mines}}
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.
====Mining, sources and production====
Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed, during which care has to be taken in order to prevent larger diamonds from being destroyed in this process and subsequently the particles are 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-ray]]s became commonplace, the separation was done with grease belts; diamonds have a stronger tendency to stick to grease than the other minerals in the ore.
Historically diamonds were known to be found only in alluvial deposits in [[southern India]].<ref name=Catelle1>{{cite book | last = Catelle | first = W.R. | title = The Diamond | publisher = John Lane Company | year = 1911}} Page 159 discussion on Alluvial diamonds in India and elsewhere as well as earliest finds </ref> India led the world in diamond production from the time of their discovery in approximately the 9th century BCE<ref name=Ball>{{cite book | last = Ball | first = V | title = Diamonds, Gold and Coal of India | publisher = London, Truebner & Co. | year = 1881}} Ball was a Geologist in British service. Chapter I, Page 1 </ref><ref name= hershey/> 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.<ref name = hershey/>
Diamond production of primary deposits (kimberlites and lamproites) only started in the 1870s after the discovery of the Diamond fields in South Africa. Production has increased over time and now an accumulated total of 4.5 billion carats have been mined since that date.<ref name=giasummer2007>{{cite journal| last = Janse | first= A J A | title= Global Rough Diamond Production Since 1870 | journal= Gems and Gemology | volume= XLIII |issue= Summer 2007| pages=98–119 |publisher=GIA year=2007 }}</ref> Interestingly 20% of that amount has been mined in the last 5 years alone and during the last ten years 9 new mines have started production while 4 more are waiting to be opened soon. Most of these mines are located in Canada, Zimbabwe, Angola, and one in Russia.<ref name = giasummer2007/>
In the US, diamonds have been found in [[Arkansas]], [[Colorado]], and [[Montana]].<ref name=DGemGLorenz>{{cite journal| last = Lorenz| first= V | title=Argyle in Western Australia: The world's richest diamondiferous pipe; its past and future| journal=Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft | volume=56 |issue=1/2| pages=35–40 |publisher=DGemG|year=2007 }}</ref><ref>[http://www.montanastandard.com/articles/2004/10/18/featuresbusiness/hjjfijicjbhdjc.txt :: The Montana Standard ::<!-- Bot generated title -->]</ref> In 2004, a startling discovery of a microscopic diamond in the US<ref>[http://www.livescience.com/environment/wyoming_diamond_041019.html Microscopic Diamond Found in Montana | LiveScience<!-- Bot generated title -->]</ref> led to the January 2008 bulk-sampling of [[kimberlite pipes]] in a remote part of [[Montana]].<ref>[http://www.deltamine.com/release2008-01-08.htm Delta :: News / Press Releases / Publications<!-- Bot generated title -->]</ref>
Today, most commercially viable diamond deposits are in Russia, [[Botswana]], Australia and the [[Democratic Republic of Congo]].<ref>{{cite web | url = http://gnn.tv/videos/2/The_Diamond_Life | title = The Diamond Life | first = Stephen | last = Marshall |coauthors = Josh Shore | year = 2004 |accessdate = 2007-03-21 }}</ref> In 2005, Russia produced almost one-fifth of the global diamond output, reports the [[British Geological Survey]]. Australia boasts the richest diamondiferous pipe with production reaching peak levels of {{convert|42|MT}} per year in the 1990s.<ref name = DGemGLorenz/>
There are also commercial deposits being actively mined in the [[Northwest Territories]] of Canada, [[Siberia]] (mostly in [[Sakha|Yakutia territory]], for example [[Mir Mine|Mir pipe]] and [[Udachnaya pipe]]), Brazil, and in Northern and Western Australia. Diamond prospectors continue to search the globe for diamond-bearing [[kimberlite]] and [[lamproite]] pipes.
[[Image:Diamond output2.PNG|thumb|right|Diamond output in 2005]]
===="Blood" diamonds====
{{main|Blood diamond}}
In some of the more politically unstable central African and west African countries, revolutionary groups have taken control of [[List of diamond mines|diamond mines]], using proceeds from diamond sales to finance their operations. Diamonds sold through this process are known as ''conflict diamonds'' or ''blood diamonds''. Major diamond trading corporations continue to fund and fuel these conflicts by doing business with armed groups. In response to public concerns that their diamond purchases were contributing to war and [[human rights abuses]] in [[central Africa]] and [[West Africa]], the [[United Nations]], 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, by providing 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. Although the Kimberley Process has been moderately successful in limiting the number of conflict diamonds entering the market, conflict diamonds smuggled to market continue to persist to some degree (approx. 2–3% of diamonds traded today are possible conflict diamonds<ref>{{cite web | url = http://www.worlddiamondcouncil.com/antwerp.shtml | title = Joint Resolution - World Federation of Diamond Bourses (WFDB) and International Diamond Manufacturers Association | publisher = World Diamond Council | date= 2000-07-19 |accessdate = 2006-11-05 }}</ref>). According to the 2006 book ''The Heartless Stone'', two major flaws still hinder the effectiveness of the Kimberley Process: the relative ease of smuggling diamonds across African borders and giving phony histories, and the violent nature of diamond mining in nations that are not in a technical state of war and whose diamonds are therefore considered "clean."<ref>{{cite book | title = The Heartless Stone: A Journey Through the World of Diamonds, Deceit, and Desire | first = Tom | last = Zoellner | publisher = St. Martin's Press | year = 2006 | isbn = 0312339690 }}</ref>
The Canadian Government has setup a body known as Canadian Diamond Code of Conduct<ref>{{cite web | title = Voluntary Code of Conduct For Authenticating Canadian Diamond Claims | url = http://www.canadiandiamondcodeofconduct.ca/html/Code_EN_Jan_06_FINAL.pdf | publisher = The Canadian Diamond Code Committee | format = PDF | year = 2006 | accessdate = 2007-10-30 }}</ref> to help authenticate Canadian diamonds. This is a very stringent tracking system of diamonds and helps protect the 'conflict free' label of Canadian diamonds.
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 mined diamonds are sold for industrial use each year, as are about 100,000 kg of synthesized diamond.
====Distribution====
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. Once purchased by sightholders, diamonds are cut and polished in preparation for sale as gemstones. The cutting and polishing of rough diamonds is a specialized skill that is concentrated in a limited number of locations worldwide. Traditional diamond cutting centers are [[Antwerp]], [[Amsterdam]], [[Johannesburg]], [[New York, New York|New York]], and [[Tel Aviv]]. Recently, diamond cutting centers have been established in China, India, and [[Thailand]]. Cutting centers with lower cost of labor, notably [[Surat]] in [[Gujarat|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.
Diamonds which have been prepared as gemstones are sold on diamond exchanges called ''bourses''. There are 26 registered diamond bourses.<ref>{{cite web | url = http://www.worldfed.com/website/boursedirectory.html | title = Bourse listing | accessdate = 2007-04-04 | work = World Federation of Diamond Bourses}}</ref> 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. Diamonds can be sold already set in jewelry, or as is increasingly popular, 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 retail sales of US$57 billion.<ref>http://www.riotintodiamonds.com/market/industry.asp</ref>
===Crater of Diamonds State Park===
The [[Crater of Diamonds State Park]] is an Arkansas State Park located near Murfreesboro in [[Pike County, Arkansas]], USA containing the only diamond bearing site in the world that is open to the public.
==Synthetics, simulants, and enhancements==
{{main|Synthetic diamond|Diamond simulant|Diamond enhancement}}
Natural diamonds have formed naturally within the earth. [[Synthetic diamond]]s are purely manufactured. A [[diamond simulant]] is defined as a non-diamond material that is used to simulate the appearance of a diamond. Diamond-simulant gems are often referred to as [[diamante]].
The gemological and industrial uses of diamond have created a large demand for rough stones. The demand for industrial diamonds has long been satisfied in large part by [[synthetic diamond]]s, 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.<ref name=Growth>{{cite web | publisher = [[American Museum of Natural History]] | url = http://www.amnh.org/exhibitions/diamonds/growing.html | title = The Nature of Diamonds: 5. Growing Diamonds | accessdate = 2007-03-21}}</ref>
The majority of commercially available synthetic diamonds are yellow in color and produced by so called High Pressure High Temperature (HPHT) processes.<ref>{{cite journal| last = Shigley et al.| first=J E| title=Gemesis Laboratory Created Diamonds| journal=Gems and Gemology| volume=38 |issue=4| pages=301–309 |publisher=GIA |year=2002 }}</ref> 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.<ref>{{cite journal| last = Shigley et al.| first=J E| title=Lab Grown Colored Diamonds from Chatham Created Gems | journal=Gems and Gemology| volume=40 |issue=2| pages=128–145|publisher=GIA | year=2004 }}</ref>
At present the annual production of gem quality synthetic diamonds is only a few thousand carats, whereas the total production of natural diamonds is around 120 million carats. Although the production of colorless synthetic diamonds is dwarfed by that of natural diamonds, one can only find one fancy colored diamond for every 10.000 colorless ones. Since almost the complete production of synthetic diamonds consists of fancy diamonds, there is a high probability that the larger fancy colored diamonds (over 1.5 carats) will be synthetic.<ref name=Donoghue>{{cite book | last = O'Donoghue | first = Michael | title = Gems | publisher = Elsevier | year = 2006}} Page 101, 102</ref>
Today, trained gemologists can generally also distinguish between natural diamonds and synthetic diamonds. Although synthetic and natural diamonds are theoretically identical and indistinguishable from each other, diamonds from each of the two categories usually incorporate their own characteristic imperfections, arising from the circumstances of their creation, that allow them to be distinguished from each other. In the case of synthetic diamonds, for example, depending on the method of production (either high-pressure/high-temperature [HPHT] produced or [[chemical vapor deposition]] [CVD] produced) and the color of the diamond (colored, D-Z color range or D-J color range), several methods of identification can be attempted by a gemologist or gemlab: CVD diamonds can usually be identified by an orange fluorescence, D-J colored diamonds can be screened through the Swiss Gemological Organization's (SSEF)<ref>E[http://www.ssef.ch/ SSEF Swiss Gemmological Institute] </ref> Diamond Spotter, and stones in the D-Z color range can be examined through the DiamondSure UV/visible spectrometer which is a tool developed by De Beers.<ref>{{cite journal| last = Welbourn| first=Christopher| title=Identification of Synthetic Diamonds: Present Status and Future Developments/Proceedings of the 4th International Gemological Symposium | journal=Gems and Gemology| volume=42 |issue=3| pages=34–35|publisher=GIA | year=2006 }}</ref> Similarly, natural diamonds usually have minor imperfections and flaws, such as inclusions of foreign material, that are not seen in synthetic diamonds. The origin of a truly ''perfect'' diamond (natural or synthetic) cannot be determined and is largely moot given that perfect diamonds are currently rare from both sources.
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. Materials which have similar gemological characteristics to diamond but are not mined or synthetic diamond are known as ''diamond simulants''. The most familiar diamond simulant to most consumers is [[cubic zirconia]] (commonly abbreviated as CZ); recently [[moissanite]] has also gained popularity and has often been mischaracterized as a diamond simulant, although it is sold and retailed as a replacement for diamond. Both CZ and moissanite are synthetically produced. However, CZ is a diamond simulant. 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 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.
Currently, trained gemologists with appropriate equipment are able to distinguish natural diamonds from simulant diamonds, and they can identify all enhanced natural diamonds. Coatings are more and more used to give a diamond simulant such as cubic zirconia a more "diamond-like" appearance. One such substance, which is heavily advertised, is what scientists refer to as "diamond-like carbon". This is an amorphous carbonaceous material that has some physical properties which are similar to that of the diamond. Advertising suggests (rightfully so or not) that such a coating would transfer some of these diamond-like properties to the coated stone, hence enhancing the diamond simulant. However, modern techniques such as [[Raman spectroscopy|Raman Spectroscopy]] should easily identify such as treatment.<ref>{{cite journal| last = Shigley | first=J E| title=Observations on new coated gemstones | journal=Gemmologie: Zeitschrift der Deutschen Gemmologischen Gesellschaft | volume=56 |issue=1/2| pages=53–56|publisher=DGemG |month= June | year= 2007 }}</ref>
Producing large synthetic diamonds threatens the business model of the diamond industry, and the ultimate effect of the ready availability of gem-quality diamonds at low cost in the future is hard to predict at this time.
The screening machine use for referring treated or enhanced diamonds as well as synthetics is the [http://www.debeersgroup.com/debeersweb/About+De+Beers/De+Beers+World+Wide/Diamond+Trading+Company+(Dtc)/DiamondSure.htm DiamondSure]{{Dead link|date=August 2008}}, and the definitive analytical machine is the [http://www.debeersgroup.com/debeersweb/About+De+Beers/De+Beers+World+Wide/Diamond+Trading+Company+(Dtc)/DiamondView.htm DiamondView]{{Dead link|date=August 2008}} produce by the DTC and supplied marketed by the GIA. All of the major diamond testing laboratories world wide are required to have these machines.
==See also==
* [[List of famous diamonds]]
* [[Diamond cubic]]
* [[Diamond drilling]]
* [[Romi Goldmuntz]]
* [[List of minerals]]
* [[Emerald]]
* [[Ruby]]
* [[Sapphire]]
==Notes==
{{reflist|2}}
==References==
<div class="references-2column">
* David, Joshua (September 2003). [http://www.wired.com/wired/archive/11.09/diamond.html "The New Diamond Age"]. ''Wired'', issue 11.09.
* De Beers Group. [http://www.debeersgroup.com/debeersweb "De Beers Group"]. Retrieved March 14, 2005.
* Epstein, Edward Jay (February 1982). [http://www.theatlantic.com/issues/82feb/8202diamond1.htm "Have You Ever Tried To Sell a Diamond?"] (subscription required). ''The Atlantic Monthly''.
* Epstein, Edward Jay (1982). [http://edwardjayepstein.com/diamond/prologue.htm "THE DIAMOND INVENTION"] (Complete book, includes "Chapter 20: [http://www.theatlantic.com/doc/198202/diamond Have you ever tried to sell a diamond?]" )
* Chaim Evevn-Zohar (2007). [http://www.mine2mistress.com "From Mine to Mistress - Corporate Strategies and Government Policies in the International Diamond Industry"] (Second edition of the book on the world diamond industry) Mining Journal Press.
* Eppler, W.F. ''Praktische Gemmologie''. Rühle-Diebner-Verlag, 1989
* Government of Gujarat (2004). [http://www.vibrantgujarat.com/ "Vibrant Gujarat: Sector Profiles"]. Retrieved March 14, 2005.
* Kjarsgaard, B.A. and Levinson, A. A. (2002). Diamonds in Canada. ''Gems & Gemology'', Vol. 38, No. 3, pp. 208–238.
* Kunz, George Frederick, ''Curious Lore of Precious Stones'', Lippincott Co., 1913
* Pagel - Theisen, Verena. ''Diamond Grading ABC: the Manual'' Rubin & Son, Antwerp, Belgium, 2001. ISBN 3-9800434-6-0
* Streeter - ''The Great Diamonds of the World'' , London, George Bell & Sons, 1882
* Taylor, W.R., Lynton A.J. & Ridd, M., (1990) [http://www.minsocam.org/ammin/AM75/AM75_1290.pdf Nitrogen defect aggregation of some Australasian diamonds: Time-temperature constraints on the source regions of pipe and alluvial diamonds.] ''American Mineralogist'', 75, pp. 1290–1310.
* Tolkowsky, Marcel (1919). ''Diamond Design: A Study of the Reflection and Refraction of Light in a Diamond.'' London: E. & F.N. Spon, Ltd. ([http://www.folds.net/diamond/index.html Web edition] as edited by Jasper Paulsen, Seattle, 2001)
* Tyson, Peter (November 2000). [http://www.pbs.org/wgbh/nova/diamond/sky.html "Diamonds in the Sky"]. Retrieved March 10, 2005.
* United Nations Department of Public Information (March 21, 2001). [http://www.un.org/peace/africa/Diamond.html "Conflict Diamonds"]. Retrieved March 10, 2005.
* Weiner, K.L., Hochleitner, R., Weiss, S., Voelstadt H. ''Diamant'', Lapis, München, 1994.
* Yarnell, Amanda (February 2, 2004). [http://pubs.acs.org/cen/coverstory/8205//8205diamonds.html "The Many Facets of Man-Made Diamonds"]. ''[[Chemical & Engineering News]]'', vol. 82, no. 5, pp 26–31.
* American Museum of Natural History. [http://www.amnh.org/exhibitions/diamonds/index.html "The Nature of Diamonds"]. Retrieved October 21, 2005.
* Carnegie Institution.[http://www.carnegieinstitution.org/diamond-13may2005/ "Very Large Diamonds Produced Very Fast"]. Retrieved November 1, 2005.
* Williams, Gardner, ''The Diamond Mines of South Africa'', New York, B.F. Buck & Co., 1905
* World Diamond Council. [http://www.worlddiamondcouncil.com/aboutwdc.shtml "About The WDC"]. Retrieved November 19, 2006.
* Wise, Richard W. "Secrets Of The Gem Trade, The Connoisseur's Guide To Precious Gemstones". (2003) Brunswick House Press. Website of book: [http://www.secretsofthegemtrade.com Secrets of the Gem Trade]
*GIA [http://www.gia.edu/pdfs/W97_fluoresce.pdf "A Contribution to the Understanding of Blue Fluorescence on the Appearance of Diamonds"]. (2007) GIA
</div>
==External links==
{{portalpar|Gemology and Jewelry|AEW diamond solo white.gif|35}}
{{commons|Diamond}}
{{wiktionary}}
*[http://www.eurostardiamond.com/diamonds/index.html Video: How a Diamond is Cut and Polished at Eurostar Diamonds International]
*[http://www.amnh.org/exhibitions/diamonds/formation.html Diamond formation phase diagrams and geotherms]
*[http://newton.ex.ac.uk/people/sque/diamond/structure/structure.html Interactive structure of bulk diamond] (Java applet)
*[http://www.pbs.org/wnet/nature/diamonds/index.html PBS Nature: Diamonds]
*[http://www.mnh.si.edu/exhibits/si-gems Smithsonian's Splendour of Diamonds exhibit]
*[http://www.farlang.com/diamonds-references Historical Diamond Books/References, 5000 pages] Most of the books mentioned as references, found online here.
*[http://thexodirectory.com/2007/12/astronomers-discovered-largest-diamond.html]
{{Allotropes of carbon}}
{{Jewellery Materials}}
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