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===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==
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