Editing Diamond (section)

==== Cutting ====
{{Main|Diamond cutting|Diamond cut}}
[[File:The Daria-e Noor (Sea of Light) Diamond from the collection of the national jewels of Iran at Central Bank of Islamic Republic of Iran.jpg|thumb|right|alt=A large rectangular pink multifaceted gemstone, set in a decorative surround. The decoration includes a row of small clear faceted gemstones around the main gem's perimeter, and clusters of gems forming a crest on one side. The crest comprises a three-pointed crown faced by two unidentifiable animals.|The [[Daria-i-Noor]] Diamond—an example of unusual diamond cut and jewelry arrangement.]]

Mined rough diamonds are converted into gems through a multi-step process called "cutting". Diamonds are extremely hard, but also brittle and can be split up by a single blow. Therefore, diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a faceted jewel where the specific angles between the facets would optimize the diamond luster, that is dispersion of white light, whereas the number and area of facets would determine the weight of the final product. The weight reduction upon cutting is significant and can be of the order of 50%.<ref name=x50>{{cite book | url = https://books.google.com/books?id=jPT6JADCqgwC&pg=PA280 | page = 280 | title = Handbook of carbon, graphite, diamond, and fullerenes: properties, processing, and applications | vauthors = Pierson HO | publisher = William Andrew | year = 1993 | isbn = 978-0-8155-1339-1 }}</ref> Several possible shapes are considered, but the final decision is often determined not only by scientific, but also practical considerations. For example, the diamond might be intended for display or for wear, in a ring or a necklace, singled or surrounded by other gems of certain color and shape.<ref name=antique>{{cite book | url = https://books.google.com/books?id=Y84qRt6nz-8C&pg=PA88 | pages = 82–102 | title = Antique jewellery: its manufacture, materials and design | vauthors = James DS | publisher = Osprey Publishing | year = 1998 | isbn = 978-0-7478-0385-0 }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Some of them may be considered as classical, such as [[Diamond cut|round]], [[Pear Cut Diamond|pear]], [[Marquise Cut Diamond|marquise]], [[Oval Cut Diamond|oval]], [[hearts and arrows]] diamonds, etc. Some of them are special, produced by certain companies, for example, [[Phoenix Cut Diamond|Phoenix]], [[Cushion Cut Diamond|Cushion]], [[Sole Mio Cut Diamond|Sole Mio]] diamonds, etc.<ref>{{cite web|url=http://www.kristallsmolensk.com/backstage/benchmarks/shapes/|title=The Classical and Special Shapes of Diamonds|publisher=kristallsmolensk.com|access-date=July 14, 2015|archive-date=July 14, 2015|archive-url=https://web.archive.org/web/20150714175156/http://www.kristallsmolensk.com/backstage/benchmarks/shapes/|url-status=live}}</ref>

The most time-consuming part of the cutting is the preliminary analysis of the rough stone. It needs to address a large number of issues, bears much responsibility, and therefore can last years in case of unique diamonds. The following issues are considered:
* The hardness of diamond and its ability to cleave strongly depend on the crystal orientation. Therefore, the crystallographic structure of the diamond to be cut is analyzed using [[X-ray diffraction]] to choose the optimal cutting directions.
* Most diamonds contain visible non-diamond inclusions and crystal flaws. The cutter has to decide which flaws are to be removed by the cutting and which could be kept.
* Splitting a diamond with a hammer is difficult, a well-calculated, angled blow can cut the diamond, piece-by-piece, but it can also ruin the diamond itself. Alternatively, it can be cut with a [[diamond saw]], which is a more reliable method.<ref name=antique/><ref>{{cite book | url = https://books.google.com/books?id=X3qe9jzYUAQC&pg=PA984 | pages = 984–992 | title = Handbook of industrial diamonds and diamond films | vauthors = Prelas MA, Popovici G, Bigelow LK | publisher = CRC Press | year = 1998 | isbn = 978-0-8247-9994-6 | access-date = November 9, 2020 | archive-date = November 9, 2023 | archive-url = https://web.archive.org/web/20231109173351/https://books.google.com/books?id=X3qe9jzYUAQC&pg=PA984#v=onepage&q&f=false | url-status = live }}</ref>

After initial cutting, the diamond is shaped in numerous stages of polishing. Unlike cutting, which is a responsible but quick operation, polishing removes material by gradual erosion and is extremely time-consuming. The associated technique is well developed; it is considered as a routine and can be performed by technicians.<ref>{{cite journal | url = https://books.google.com/books?id=i9kDAAAAMBAJ&pg=PA760 | pages = 760–764 | title = Gem Cutting | journal = [[Popular Mechanics]] | year = 1940 | volume = 74 | issue = 5 | issn = 0032-4558 | access-date = November 9, 2020 | archive-date = November 9, 2023 | archive-url = https://web.archive.org/web/20231109173258/https://books.google.com/books?id=i9kDAAAAMBAJ&pg=PA760#v=onepage&q&f=false | url-status = live }}</ref> After polishing, the diamond is reexamined for possible flaws, either remaining or induced by the process. Those flaws are concealed through various [[diamond enhancement]] techniques, such as repolishing, crack filling, or clever arrangement of the stone in the jewelry. Remaining non-diamond inclusions are removed through laser drilling and filling of the voids produced.<ref name=read>{{cite book | url = https://books.google.com/books?id=t-OQO3Wk-JsC&pg=PA166 | pages = 165–166 | title = Gemmology | vauthors = Read PG | publisher = Butterworth-Heinemann | year = 2005 | isbn = 978-0-7506-6449-3 | access-date = November 9, 2020 | archive-date = November 9, 2023 | archive-url = https://web.archive.org/web/20231109173801/https://books.google.com/books?id=t-OQO3Wk-JsC&pg=PA166#v=onepage&q&f=false | url-status = live }}</ref>