Editing Ruby (section)

==Synthesis and imitation==
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|image1=Artificial ruby hemisphere under a normal light.jpg
|image2=Artificial ruby hemisphere under a monochromatic light.jpg
||caption2=Artificial ruby under a normal light (top) and under a green laser light (bottom). Red light is emitted.}}
In 1837, Gaudin made the first synthetic rubies by fusing [[potash alum]] at a high temperature with a little chromium as a pigment. In 1847, [[Jacques-Joseph Ebelmen|Ebelmen]] made white sapphire by fusing [[alumina]] in boric acid. In 1877, [[Edmond Frémy]] and industrial glass-maker Charles Feil made crystal [[corundum]] from which small stones could be cut. In 1887, Fremy and [[Auguste Verneuil]] manufactured artificial ruby by fusing BaF{{sub|2}} and Al{{sub|2}}O{{sub|3}} with a little chromium at [[Incandescence|red heat]].

In 1903, Verneuil announced he could produce synthetic rubies on a commercial scale using this flame fusion process, later also known as the [[Verneuil process]].<ref>{{cite web|url = http://www.farlang.com/gemstones/bahadur_handbook_of_precious_stones/page_067|title = Bahadur: a Handbook of Precious Stones|year = 1943|access-date = 19 August 2007|url-status = live|archive-url = https://web.archive.org/web/20070927020704/http://www.farlang.com/gemstones/bahadur_handbook_of_precious_stones/page_067|archive-date = 27 September 2007|df = mdy-all}}</ref> By 1910, Verneuil's laboratory had expanded into a 30 furnace production facility, with annual gemstone production having reached {{convert|1000|kg|lb|-3}} in 1907.

Other processes in which synthetic rubies can be produced are through [[Czochralski process|Czochralski's pulling process]], flux process, and the [[hydrothermal synthesis|hydrothermal process]]. Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curved [[Striation (geology)|striae]] and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a perfect ruby), in which case it will be suspected of being artificial. [[Dopant]]s are added to some manufactured rubies so they can be identified as synthetic, but most need [[gemology|gemological]] testing to determine their origin.

Synthetic rubies have technological uses as well as gemological ones. Rods of synthetic ruby are used to make [[ruby laser]]s and [[maser]]s. The first working laser was made by [[Theodore Maiman|Theodore H. Maiman]] in 1960.<ref name="maiman">{{cite journal |last=Maiman |first=T.H. |author-link=Theodore Harold Maiman |year=1960 |title=Stimulated optical radiation in ruby |journal=Nature|volume=187 |issue=4736 |pages=493–494 |doi=10.1038/187493a0 |bibcode=1960Natur.187..493M|s2cid=4224209 }}</ref> Maiman used a solid-state light-pumped synthetic ruby to produce red laser light at a wavelength of 694 nanometers (nm). Ruby lasers are still in use.

Rubies are also used in applications where high hardness is required such as at wear-exposed locations in mechanical clockworks, or as scanning probe tips in a [[coordinate measuring machine]].{{citation needed|date=May 2022}}

Imitation rubies are also marketed. Red [[spinel]]s, red [[garnet]]s, and colored glass have been falsely claimed to be rubies. Imitations go back to Roman times and already in the 17th century techniques were developed to color foil red—by burning scarlet wool in the bottom part of the furnace—which was then placed under the imitation stone.<ref>{{cite web|url = http://www.farlang.com/gemstones/nicols-history-gemstones/page_036|title = Thomas Nicols: A Lapidary or History of Gemstones|year = 1652|access-date = 19 August 2007|url-status = live|archive-url = https://web.archive.org/web/20070819165714/http://www.farlang.com/gemstones/nicols-history-gemstones/page_036|archive-date = 19 August 2007|df = mdy-all}}</ref> Trade terms such as [[balas ruby]] for red spinel and [[rubellite]] for red [[tourmaline]] can mislead unsuspecting buyers. Such terms are therefore discouraged from use by many gemological associations such as the Laboratory Manual Harmonisation Committee (LMHC).