Editing Gemstone (section)

==Treatment==
Gemstones are often treated to enhance the color or clarity of the stone.<ref>{{Cite book |last=Nassau |first=Kurt |title=Gemstone enhancement: heat, irradiation, impregnation, dyeing, and other treatments which alter the appearance of gemstones, and the detection of such treatments |date=1984 |publisher=Butterworths |isbn=978-0-408-01447-2 |location=London u.a}}</ref> In some cases, the treatment applied to the gemstone can also increase its durability. Even though natural gemstones can be transformed using the traditional method of cutting and polishing, other treatment options allow the stone's appearance to be enhanced.<ref name="gia.edu">{{Cite web |title=An Introduction to Gem Treatments |url= https://www.gia.edu/gem-treatment |access-date=2023-03-31 |website=www.gia.edu |language=en |archive-date=April 6, 2023 |archive-url=https://web.archive.org/web/20230406200208/https://www.gia.edu/gem-treatment |url-status=live }}</ref> Depending on the type and extent of treatment, they can affect the value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone.<ref name = enhancement>{{cite book |title=Gemstone Enhancement: History, Science and State of the Art |first=Kurt |last=Nassau |year=1994 |publisher=Butterworth Heinemann |place=Oxford |edition=2nd |isbn=9780750617970 |oclc=28889342}}</ref>

=== Early history ===
Before modern-day tools, thousands of years ago, a variety of techniques were used to treat and enhance gemstones. Some of the earliest methods of gemstone treatment date back to the Minoan Age, for example foiling, in which metal foil is used to enhance a gemstone's colour.<ref>{{Cite web |last=Nassau |first=Kurt |date=1984 |title=The Early History of Gemstone Treatments |url=https://www.gia.edu/doc/The-Early-History-of-Gemstone-Treatments.pdf |access-date=March 31, 2023 |archive-date=January 2, 2023 |archive-url=https://web.archive.org/web/20230102015109/https://www.gia.edu/doc/The-Early-History-of-Gemstone-Treatments.pdf |url-status=live }}</ref> Other methods recorded 2000 years ago in the book ''[[Natural History (Pliny)|Natural History]]'' by [[Pliny the Elder]] include oiling and dyeing/staining.

=== Heat ===
Heat can either improve or spoil gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating is a common practice. Most [[citrine quartz|citrine]] is made by heating [[amethyst]], and partial heating with a strong gradient results in "[[ametrine]]" – a stone partly amethyst and partly citrine. [[Aquamarine (gemstone)|Aquamarine]] is often heated to remove yellow tones, or to change green colors into the more desirable blue, or enhance its existing blue color to a deeper blue.<ref name = enhancement/>

Nearly all [[tanzanite]] is heated at low temperatures to remove brown undertones and give a more desirable blue / purple color.<ref>{{cite web |url=http://www.lapigems.com/blog/post/2013/01/17/Tanzanite-Heating-The-Facts.aspx |title=Tanzanite heating – the science |archive-url=https://web.archive.org/web/20160620222334/http://www.lapigems.com/blog/post/2013/01/17/Tanzanite-Heating-The-Facts.aspx |archive-date=2016-06-20 |df=dmy-all}}</ref> A considerable portion of all [[sapphire]] and [[ruby]] is treated with a variety of heat treatments to improve both color and clarity.

When jewelry containing diamonds is heated for repairs, the diamond should be protected with [[boric acid]]; otherwise, the diamond, which is pure carbon, could be burned on the surface or even burned completely up. When jewelry containing [[sapphires]] or [[rubies]] is heated, those stones should not be coated with boric acid (which can etch the surface) or any other substance. They do not have to be protected from burning, like a diamond (although the stones do need to be protected from heat stress fracture by immersing the part of the jewelry with stones in the water when metal parts are heated).

===Radiation===
{{Main|Gemstone irradiation}}
The irradiation process is widely practiced in [[jewelry industry]]<ref name="Omi Rela 2021 p1">{{cite book |last1=Omi |first1=Nelson M. |year=2007 |title=Gemstone Dedicated Gamma Irradiator Development: Proceedings of the INAC 2007 International Nuclear Atlantic Conference |url=https://www.ipen.br/biblioteca/2007/inac/11996.pdf |access-date=October 21, 2022 |first2=Paulo R. |last2=Rela |publisher=Associação Brasileira de Energia Nuclear |isbn=978-85-99141-02-1 |archive-date=October 21, 2022 |archive-url=https://web.archive.org/web/20221021175845/https://www.ipen.br/biblioteca/2007/inac/11996.pdf |page=1}}</ref> and enabled the creation of gemstone colors that do not exist or are extremely rare in nature.<ref name="Hurlbut p170">{{cite book |last1=Hurlbut |first1=Cornelius S. |last2=Kammerling |first2=Robert C. |title=Gemology |year=1991 |publisher=[[Wiley-Interscience]] |url=https://batch.libretexts.org/print/Letter/Finished/geo-3164/Full.pdf|archive-date=November 4, 2022|archive-url=https://web.archive.org/web/20221104150452/https://batch.libretexts.org/print/Letter/Finished/geo-3164/Full.pdf |isbn=0-471-52667-3 |access-date=November 4, 2022 |url-status=live| via=[[LibreTexts]] |page=170}}</ref> However, particularly when done in a [[nuclear reactor]], the processes can make gemstones radioactive. Health risks related to the residual radioactivity of the treated gemstones have led to government regulations in many countries.<ref name="Hurlbut p170"/><ref>{{cite web |url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/irradiated-gemstones.html |title=Backgrounder on Irradiated Gemstones |author=Nuclear Regulatory Commission |publisher=The U.S. [[Nuclear Regulatory Commission]] |date=April 2019 |access-date=November 12, 2022 |archive-date=September 1, 2022 |archive-url=https://web.archive.org/web/20220901040847/http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/irradiated-gemstones.html |url-status=live}} {{USGovernment}}</ref>

Virtually all [[blue topaz]], both the lighter and the darker blue shades such as "London" blue, has been irradiated to change the color from white to blue. Most green quartz (Oro Verde) are also irradiated to achieve the yellow-green color. Diamonds are mainly irradiated to become blue-green or green, although other colors are possible. When light-to-medium-yellow diamonds are treated with gamma rays they may become green; with a high-energy electron beam, blue.<ref name=Rossman_70>{{cite journal|last=Rossman |first=George R. |title=Color in Gems: The New Technologies |url=https://www.gia.edu/doc/Color-In-Gems-The-New-Technologies.pdf |periodical=[[Gems & Gemology]] |volume= 17|issn=0016-626X |issue= 2|date=Summer 1981 |page=70 |publisher=Gemological Institute of America |doi=10.5741/GEMS.17.2.60 |doi-access=free |bibcode=1981GemG...17...60R |archive-url=https://web.archive.org/web/20221112041127/https://www.gia.edu/doc/Color-In-Gems-The-New-Technologies.pdf |archive-date=November 12, 2022}}</ref>

===Waxing/oiling===
Emeralds containing natural fissures are sometimes filled with [[wax]] or [[oil]] to disguise them. This wax or oil is also colored to make the emerald appear of better color as well as clarity. Turquoise is also commonly treated in a similar manner.

===Fracture filling===
[[File:Emerald Fracture Filled Rainbow.jpg|thumb|alt=The foreign material inside this fracture-filled emerald appears rainbow-colored under darkfield illumination.|The foreign material inside this fracture-filled emerald appears rainbow-colored under darkfield illumination.]]
Fracture filling has been in use with different gemstones such as diamonds, emeralds, and sapphires. In 2006 "glass-filled rubies" received publicity. Rubies over 10 carats (2&nbsp;g) with large fractures were filled with lead glass, thus dramatically improving the appearance (of larger rubies in particular). Such treatments are fairly easy to detect.

=== Bleaching ===
[[File:Pearl_from_Pinctada_maxima_(gold-lipped_pearl_oyster)_1.jpg|thumb|Pearls are a gemstone that is commonly treated with hydrogen peroxide to remove unwanted colours.]]
Another treatment method that is commonly used to treat gemstones is bleaching. This method uses a chemical in order to reduce the colour of the gem. After bleaching, a combination treatment can be done by dying the gemstone once the unwanted colours are removed. Hydrogen peroxide is the most commonly used product used to alter gemstones and have notably been used to treat jade and pearls. The treatment of bleaching can also be followed by impregnation, which allows the gemstone's durability to be increased.<ref name="gia.edu" />