"දියමන්ති" හි සංශෝධන අතර වෙනස්කම්
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In 1772, [[Antoine Lavoisier]] used a lens to concentrate the rays of the sun on a diamond in an atmosphere of [[oxygen]], and showed that the only product of the combustion was [[carbon dioxide]], proving that diamond is composed of carbon. Later in 1797, [[Smithson Tennant]] repeated and expanded that experiment. By demonstrating that burning diamond and graphite releases the same amount of gas he established the chemical equivalence of these substances.<ref name=hazen/>
The most familiar use of diamonds today is as gemstones used for [[adornment]], a use which dates back into antiquity. The [[Dispersion (optics)|dispersion]] of white light into [[spectral color]]s is the primary gemological characteristic of gem diamonds. In the 20th century, experts in 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 (unit)|carat]]'', ''cut'', ''color'', and ''clarity''.<ref>{{cite book|url=http://books.google.com/?id=DIWEi5Hg93gC&pg=PA42|page=42|author=Hesse, R. W.|title=Jewelrymaking through history| publisher=Greenwood Publishing Group| year= 2007|isbn=0-313-33507-9}}</ref> A large, flawless diamond is known as a [[Paragon (diamond)|paragon]].
==Material properties==
{{Main|Material properties of diamond|Crystallographic defects in diamond}}
[[File:Carbon basic phase diagram.png|thumb|left|Theoretically predicted [[phase diagram]] of carbon]]
[[File:Diamond and graphite2.jpg|thumb|alt=Four panels. First, seven clear faceted gems, six small and a large one. Second, black material with uneven surface. Third, three parallel atomic sheets, each resembling a chicken wire hedge. Fourth, a boxed atomic structure containing tetrahedrally arranged balls connected by 0.15 nm bonds.|Diamond and graphite are two [[allotrope]]s 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 ([[Orbital hybridisation|sp<sup>3</sup>]]) that crystallizes into the [[Diamond cubic|diamond lattice]] which is a variation of the [[face centered cubic]] structure. Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Most notable are its extreme hardness and thermal conductivity (900–{{val|2320|u=W·m{{Sup|−1}}·K{{Sup|−1}}}}),<ref name=PNU>
{{cite journal
|last=Wei |first=L.
|title=Thermal conductivity of isotopically modified single crystal diamond
|journal=Physical Review Letters
|volume=70 |page=3764
|year=1993
|doi =10.1103/PhysRevLett.70.3764
|last2=Kuo
|first2=P. K.
|last3=Thomas
|first3=R. L.
|last4=Anthony
|first4=T.
|last5=Banholzer
|first5=W.
|pmid=10053956
|bibcode=1993PhRvL..70.3764W
|issue=24
|pages=3764–3767
}}</ref> as well as wide [[bandgap]] and high optical dispersion.<ref name=walker/> Above {{val|1700|ul=degC}} ({{val|1973|ul=K}} / {{val|3583|ul=degF}}) in [[vacuum]] or oxygen-free atmosphere, diamond converts to graphite; in air, transformation starts at ~{{val|700|u=degC}}.<ref>{{cite journal| doi =10.1016/S0925-9635(01)00673-2| title =The oxidation of (100) textured diamond| year =2002| author =John, P| journal =Diamond and Related Materials| volume =11| page=861| issue =3–6}}</ref> Diamond's ignition point is 720 - {{val|800|u=degC}} in oxygen and 850 - {{val|1000|u=degC}} in air.<ref name=DBS>{{cite web|publisher=DiamondBladeSelect.com|title=Basic Properties of Diamond|url=http://www.diamondbladeselect.com/knowledge/basic-properties-of-diamond/}}</ref> Naturally occurring diamonds have a density ranging from 3.15–{{val|3.53|u=g/cm3}}, with pure diamond close to {{val|3.52|u=g/cm3}}.<ref name=mindat>{{cite web|publisher=Mindat|title=Diamond|url=http://www.mindat.org/min-1282.html|accessdate=2009-07-07}}</ref> The chemical bonds that hold the carbon atoms in diamonds together are weaker than those in graphite. In diamonds, the bonds form an inflexible three-dimensional lattice, whereas in graphite, the atoms are tightly bonded into sheets, which can slide easily over one another, making the overall structure weaker.<ref name=Pop>{{cite journal
|last=Gray |first=Theodore
|title=Gone in a Flash
|journal=Popular Science
|page=70
|month=September
|year=2009
}}</ref>
<!--Research results published in an article in the scientific journal ''[[Nature (journal)|Nature]]'' in 2010 suggest that at ultrahigh pressures and temperatures (about 10&nbsp;million atmospheres or 1&nbsp;TPa and 50,000&nbsp;°C) diamond behaves as a metallic fluid. The extreme conditions required for this to occur are present in the [[gas giant]]s of [[Neptune]] and [[Uranus]]. Both planets are made up of approximately 10 percent carbon and could hypothetically contain oceans of liquid carbon. Since large quantities of metallic fluid can affect the magnetic field, this could serve as an explanation as to why the geographic and magnetic poles of the two planets are unaligned.<ref>{{cite news |title=Diamond oceans possible on Uranus, Neptune|author=Eric Bland |newspaper=Discovery News |date=Fri Jan 15, 2010 |url=http://news.discovery.com/space/diamond-oceans-jupiter-uranus.html |accessdate=Sat January 16, 2010}}</ref><ref>{{cite journal|doi=10.1038/nphys1491|title=Diamond: Molten under pressure|author=Silvera, Isaac|journal=Nature Physics |volume=6|page=9|year=2010|issue=1}}</ref>-->
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