Editing Diamond cut (section)

== History ==
=== Ancient India ===
[[File:British Museum The Islamic world Necklace Kundan India 21022019 7703.jpg|thumb|Indian gold necklace with [[pearl]]s, [[Ruby|rubies]], [[emerald]]s, and conservatively cut diamonds mounted in traditional [[Bezel (jewellery)|bezel]] settings.]]
The process of diamond cutting has been known in the [[Indian subcontinent]] as early as the sixth century AD. A sixth-century treatise [[Ratna Pariksha|Ratnapariksa]], or "Appreciation of Gems", states that the best form in which to have the diamond is in its perfect natural octahedral crystal form, and not as a cut stone, indicating that diamond cutting was widespread practice.<ref>{{Cite web|url=https://www.penn.museum/sites/expedition/the-lapidary-arts-in-islam/|title=Expedition Magazine – Penn Museum|website=www.penn.museum|access-date=2020-03-31}}</ref> Al Beruni also describes the process of diamond grinding using lead plate in the 11th century AD.<ref>{{Cite web|url=https://www.langantiques.com/university/a-history-of-diamond-cutting/|title=A History Of Diamond Cutting {{!}} Antique Jewelry University|language=en-US|access-date=2020-03-31}}</ref> Agastimata, written before 10th century AD, states:<ref>{{Citation|title=Agastimata book|date=2009|work=Dictionary of Gems and Gemology|pages=10|editor-last=Manutchehr-Danai|editor-first=Mohsen|publisher=Springer|language=en|doi=10.1007/978-3-540-72816-0_262|isbn=978-3-540-72816-0}}</ref>
{{Quotation|text=The diamond cannot be cut by means of metals and gems of other species; but it also resists polishing, the diamond can only be polished by means of other diamonds|author=|title=Agastimata|source=}}
A 12th- or early 13th-century diamond ring attributed to [[Muhammad of Ghor|Muhammad Ghauri]] contains two diamonds whose crude octahedral natural states are maintained, but they are in limpid condition, exhibiting diamond polishing and shaping predating Europe, where the first diamond processing dates back to the mid-14th century AD.<ref>{{Cite web|url=https://www.bonhams.com/auctions/10814/lot/293/|title=Bonhams : Two highly important Sultanate gem-set gold Rings made for Mu'izz al-Din Muhammad bin Sam (AH 569-602/ AD 1173–1206), the first Muslim conqueror of Delhi (2)|website=www.bonhams.com|access-date=2020-03-31}}</ref> As of today, few diamonds with ancient Mughal-style faceting are known.<ref>{{Cite web|url=https://gemconcepts.net/mughal-cut-diamonds-the-search-continues/ |title=Mughal Cut Diamonds – The Search Continues|language=en-US|access-date=2024-01-02}}</ref>

=== Europe ===
[[File:The Three Brothers detail.png|thumb|300px|Details from two portraits of [[Elizabeth I]], showing several point cut diamonds, including the [[Three Brothers (jewel)|Three Brothers]] (three rectangular red [[spinel]]s) around a blue diamond]]
[[File:Diamond ring from Tåsinge.jpg|thumb|17th-century gold ring set with seven octahedral polished diamonds found in [[Tåsinge]], Denmark]]
The history of diamond cuts in Europe can be traced to the late [[Middle Ages]], before which time diamonds were employed in their natural [[Octahedron|octahedral]] state—anhedral (poorly formed) diamonds simply were not used in jewelry. The first "improvements" on nature's design involved a simple polishing of the octahedral crystal faces to create even and unblemished facets, or to fashion the desired octahedral shape out of an otherwise unappealing piece of rough. This was called the point cut, and dates from the mid-14th century; by 1375 there was a [[guild]] of diamond polishers at [[Nuremberg]]. By the mid-15th century, the point cut began to be improved upon: the top of the octahedron would be polished or ground off, creating the table cut. The importance of a [[culet]] was also realized, and some table-cut stones may possess one. The addition of four corner facets created the old single cut (or old eight cut). Neither of these early cuts would reveal what diamond is prized for today: its strong [[dispersion (optics)|dispersion]] or fire. At the time, diamond was valued chiefly for its [[adamantine lustre]] and superlative hardness; a table-cut diamond would appear black to the eye, as they do in paintings of the era. For this reason, colored gemstones such as [[ruby]] and [[sapphire]] were far more popular in jewelry of the era.

In or around 1476, [[Lodewyk van Bercken]], a [[Flemish people|Flemish]] polisher of [[Bruges]], introduced the technique of absolute symmetry in the disposition of facets using a device of his own invention, the [[scaif]]. He cut stones in the shape known as [[Pendeloque cut|pendeloque]] or [[briolette]]; these were pear-shaped with triangular facets on both sides. About the middle of the 16th century, the rose or rosette was introduced in [[Antwerp]]: it also consisted of triangular facets arranged in a symmetrical radiating pattern, but with the bottom of the stone left flat—essentially a crown without a pavilion. Many large, famous Indian diamonds of old (such as the [[Orlov (diamond)|Orloff]] and [[Sancy]]) also feature a rose-like cut, although these Indian rose diamonds were most likely cut by European lapidaries.<ref>{{Cite web |title=Volume 35 / No. 1 / 2016 {{!}} Gem-A |url=https://gem-a.com/publications/the-journal-of-gemmology/volume-35-no-1-2016/ |access-date=2025-04-21 |page=57 |language=en-US}}</ref> The rose cut continued to evolve, with its depth, number and arrangements of facets being tweaked.

The first [[Brilliant (diamond cut)|brilliant]] cuts were introduced in the middle of the 17th century. Known as Mazarins, they had 17 facets on the crown (upper half). They are also called double-cut brilliants as they are seen as a step up from old single cuts. [[Vincent Peruzzi]], a [[Venice|Venetian]] polisher, later increased the number of crown facets from 17 to 33 (triple-cut or Peruzzi brilliants), thereby significantly increasing the fire and brilliance of the cut gem, properties that in the Mazarin were already incomparably better than in the rose. Yet Peruzzi-cut diamonds, when seen nowadays, seem exceedingly dull compared to modern-cut brilliants. {{Anchor|Cushion cut}}Because the practice of [[bruting]] had not yet been developed, these early brilliants were all rounded squares or rectangles in cross-section (rather than circular). Given the general name of '''cushion'''—what are known today as old mine cuts—these were common by the early 18th century.

Around 1860, American jeweler Henry Dutton Morse opened the first American diamond-cutting factory in Boston. Assuming that smaller but more beautiful gems would sell better, he went against the dogma of conserving diamond weight at all costs and scientifically studied refraction in diamonds, by around 1870 developing what was called the old European cut much later.<ref>{{Cite web |title=Book Review: American Cut, The First 100 Years by Al Gilbertson {{!}} GemWise / rwwise.com |url=https://www.thefrenchblue.com/rww_blog/2007/11/12/book-review-american-cut-the-first-100-years-by-al-gilbertson/ |access-date=2023-12-21 |language=en-US}}</ref> This cut had a shallower pavilion, more rounded shape thanks to Morse's foreman Charles M. Field, who developed mechanical diamond-bruting machine to replace manual rounding (the two also introduced [[Gauge (instrument)|dimensional gauges]] to the industry), and different arrangement of facets. The old European cut was the forerunner of modern brilliants and was the most advanced in use during the 19th century and first two decades of the 20th century, prevailing on the market from about 1890 until about 1930.<ref>{{Cite web |title=Old European Cut Diamonds |url=https://www.jewelsbygrace.com/blogs/news/the-old-european-cut-diamond |access-date=2023-12-21 |website=Jewels by Grace |language=en}}</ref> As compared with the modern round brilliant cut, it is inferior in brilliance but superior in fire.<ref>{{Cite web |last=Federman |first=David |date=2022-08-10 |title=Gem Portrait: Old European Cut Diamonds |url=https://blog.worthy.com/knowledge-center/diamonds/old-european-cut-diamonds/ |access-date=2023-12-21 |website=Worthy |language=en-US}}</ref>

[[File:Raw light brown diamond crystal cut in half 7.jpg|thumb|upright|A light brown [[Rough diamond|natural]] diamond crystal sawed in half, reflected on glass]]
Around the turn of the century, the development of motorized rotary [[saw]]s for cutting diamonds, patented in 1901 by John H. G. Stuurman<ref>{{US patent|694215A}}</ref> and in 1902 by Ernest G. H. Schenck,<ref>{{US patent|732118A}}</ref> gave cutters creative freedom to separate small stones not detachable by cleaving as they wish and allowed them to waste less. These diamond saws and good jewelry [[lathe]]s enabled the development of modern diamond cutting and diamond cuts, chief among them the round brilliant cut. In 1919, [[Marcel Tolkowsky]] analyzed this cut: his calculations took both brilliance (the amount of white light reflected) and fire into consideration, creating a delicate balance between the two.<ref name="tolk">{{cite book|title=Diamond Design|url=http://www.folds.net/diamond/index.html|author=Marcel Tolkowsky|year=1919|publisher=Spon & Chamberlain}}</ref> Tolkowsky's calculations would serve as the basis for all future brilliant cut modifications and standards.

Tolkowsky's model of the "ideal" cut is not perfect. The original model served as a general guideline, and did not explore or account for several aspects of diamond cut:<ref>{{cite web|url=http://www.gia.edu/research/1383/2280/article_detail.cfm|title=What did Marcel Tolkowsky really say?|url-status=dead|archive-url=https://web.archive.org/web/20060827055844/http://www.gia.edu/research/1383/2280/article_detail.cfm|archive-date=2006-08-27}}</ref>

<blockquote>Because every facet has the potential to change a light ray's plane of travel, ''every facet must be considered in any complete calculation of light paths''.
Just as a two-dimensional slice of a diamond provides incomplete information about the three-dimensional nature of light behavior inside a diamond, this two-dimensional slice also provides incomplete information about light behavior ''outside'' the diamond. A diamond's panorama is three-dimensional. Although diamonds are highly symmetrical, light can enter a diamond from many directions and many angles. This factor further highlights the need to reevaluate Tolkowsky's results, and to recalculate the effects of a diamond's proportions on its appearance aspects. ...</blockquote>

<blockquote>Another important point to consider is that Tolkowsky did not follow the path of a ray that was reflected more than twice in the diamond. However, we now know that a diamond's appearance is composed of many light paths that reflect considerably more than two times within that diamond. Once again, we can see that Tolkowsky's predictions are helpful in explaining optimal diamond performance, but they are incomplete by today's technological standards.</blockquote>

Tolkowsky's guidelines, while revolutionary in their day, are not a definitive solution to the problem of finding the optimum proportions of a round brilliant cut diamond.

In the 1970s, Bruce Harding developed another mathematical model for gem design.
Since then, several groups have used computer models<ref name=tolk /><ref>{{cite web|url=http://www.cutstudy.com|title=Russian gemmological server|access-date=2009-08-08}}</ref> and specialized scopes to design diamond cuts.

The world's top diamond-cutting and -polishing center is India. It processes 11 out of 12 diamonds in jewelry worldwide. The sector employs 1.3 million people and accounts for 14% of India's $80 billion of annual exports. Its share in the world polished diamond market is 92% by pieces and 55% by value.