Editing Diamond (section)

=== Synthetics ===
{{Main|Synthetic diamond}}

Synthetic diamonds are diamonds manufactured in a laboratory, as opposed to diamonds mined from the Earth. The gemological and industrial uses of diamond have created a large demand for rough stones. This demand has been satisfied in large part by synthetic diamonds, which have been manufactured by various processes for more than half a century. However, in recent years it has become possible to produce gem-quality synthetic diamonds of significant size.<ref name="AMNH"/> It is possible to make colorless synthetic gemstones that, on a molecular level, are identical to natural stones and so visually similar that only a gemologist with special equipment can tell the difference.<ref name="bain">{{cite web |url=http://www.bain.com/Images/PR_BAIN_REPORT_The_global_diamond_industry.pdf |archive-url=https://web.archive.org/web/20120131062348/http://www.bain.com/Images/PR_BAIN_REPORT_The_global_diamond_industry.pdf |archive-date=January 31, 2012 |url-status=live|title=The Global Diamond Industry: Lifting the Veil of Mystery|publisher=[[Bain and Company|Bain & Company]]|access-date=January 14, 2012}}</ref>

The majority of commercially available synthetic diamonds are yellow and are produced by so-called ''high-pressure high-temperature'' ([[HPHT]]) processes.<ref>{{cite journal| vauthors = Shigley JE, Abbaschian R |title=Gemesis Laboratory Created Diamonds|journal=Gems & Gemology|volume=38|issue=4|pages=301–309|year=2002|doi=10.5741/GEMS.38.4.301|doi-access=free|bibcode=2002GemG...38..301S }}</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 [[Gemstone irradiation|irradiation]] after synthesis.<ref>{{cite journal| vauthors = Shigley JE, Shen AH, Breeding CM, McClure SF, Shigley JE |title=Lab Grown Colored Diamonds from Chatham Created Gems|journal=Gems & Gemology|volume=40|issue=2|pages=128–145|year=2004|doi=10.5741/GEMS.40.2.128|doi-access=free|bibcode=2004GemG...40..128S }}</ref>

Another popular method of growing synthetic diamond is [[chemical vapor deposition]] (CVD). The growth occurs under low pressure (below atmospheric pressure). It involves feeding a mixture of gases (typically {{nowrap|1 to 99 [[methane]]}} to [[hydrogen]]) into a chamber and splitting them into chemically active [[radical (chemistry)|radicals]] in a [[plasma (physics)|plasma]] ignited by [[microwaves]], [[hot filament]], [[electric arc|arc discharge]], [[welding torch]], or [[laser]].<ref>{{cite journal | vauthors = Werner M, Locher R  |title=Growth and application of undoped and doped diamond films |journal=Reports on Progress in Physics |volume=61 |pages=1665–1710 |year=1998 |doi=10.1088/0034-4885/61/12/002 |issue=12 |bibcode=1998RPPh...61.1665W|s2cid=250878100 }}</ref> This method is mostly used for coatings, but can also produce single crystals several millimeters in size (see picture).<ref name=yarnell/>

As of 2010, nearly all 5,000&nbsp;million carats (1,000{{nbsp}}tonnes) of synthetic diamonds produced per year are for industrial use. Around 50% of the 133&nbsp;million carats of natural diamonds mined per year end up in industrial use.<ref name="bain"/><ref>{{cite web|url=https://www.cnbc.com/2012/08/27/the-billion-dollar-business-of-diamonds-from-mining-to-retail.html|vauthors=Pisani B|title=The Business of Diamonds, From Mining to Retail|publisher=[[CNBC]]|date=August 27, 2012|access-date=September 9, 2017|archive-date=July 7, 2017|archive-url=https://web.archive.org/web/20170707001321/http://www.cnbc.com/id/48782968|url-status=live}}</ref> Mining companies' expenses average 40 to 60&nbsp;US dollars per carat for natural colorless diamonds, while synthetic manufacturers' expenses average {{nowrap|$2,500 per carat}} for synthetic, gem-quality colorless diamonds.<ref name="bain"/>{{rp|79}} However, a purchaser is more likely to encounter a synthetic when looking for a fancy-colored diamond because only 0.01% of natural diamonds are fancy-colored, while most synthetic diamonds are colored in some way.<ref>{{cite book|url=https://books.google.com/books?id=zNicdkuulE4C&pg=PA428|pages=426–430|title=Industrial Minerals & Rocks|vauthors=Kogel JE|publisher=SME|year=2006|isbn=978-0-87335-233-8|access-date=November 9, 2020|archive-date=November 9, 2023|archive-url=https://web.archive.org/web/20231109173917/https://books.google.com/books?id=zNicdkuulE4C&pg=PA428#v=onepage&q&f=false|url-status=live}}</ref>

<gallery widths="200px" heights="180px">
File:HPHTdiamonds2.JPG|alt=Six crystals of cubo-octahedral shapes, each about 2 millimeters in diameter. Two are pale blue, one is pale yellow, one is green-blue, one is dark blue and one green-yellow.|Synthetic diamonds of various colors grown by the high-pressure high-temperature technique
File:Apollo synthetic diamond.jpg|alt=A round, clear gemstone with many facets, the main face being hexagonal, surrounded by many smaller facets.|Colorless gem cut from diamond grown by chemical vapor deposition
</gallery>