View source for Gemstone

{{short description|Piece of mineral crystal used to make jewelry}}
{{Redirect-several|Gemstone|Gems|Gem|Jewels|Precious stone}}
{{Use mdy dates|date=February 2023}}
[[File:Cardinal gems.png|thumb|250px|Group of precious and semiprecious stones—both uncut and faceted—including (''clockwise from top left'') [[diamond]], uncut synthetic [[sapphire]], [[ruby]], uncut [[emerald]], and [[amethyst]] crystal cluster.]]

A '''gemstone''' (also called a '''fine gem''', '''jewel''', '''precious stone''', '''semiprecious stone''', or simply '''gem''') is a piece of [[mineral]] [[crystal]] which, when cut or polished, is used to make [[jewellery|jewelry]] or other [[adornment]]s.<ref name = oxford>{{cite web|url =https://www.lexico.com/en/definition/gemstone|archive-url =https://web.archive.org/web/20200321174957/https://www.lexico.com/en/definition/gemstone|url-status =dead|archive-date =March 21, 2020|title = Gemstone|website = Lexico|publisher = Oxford University Press}}</ref><ref>[http://mw1.merriam-webster.com/dictionary/gemstone Webster Online Dictionary] {{webarchive|url=https://web.archive.org/web/20070603091355/http://mw1.merriam-webster.com/dictionary/gemstone |date=2007-06-03 }}</ref><ref>{{cite book|title=Simply Gemstones: Designs for Creating Beaded Gemstone Jewelry|last=Alden|first=Nancy|date=2009|publisher=[[Random House]]|location=New York, NY|isbn=978-0-307-45135-4|page=136|url=https://books.google.com/books?id=YWqLSol_bEwC}}</ref> Certain [[Rock (geology)|rocks]] (such as [[lapis lazuli]], [[opal]], and [[obsidian]]) and occasionally [[organic chemistry|organic]] materials that are not minerals (such as [[amber]], [[Jet (gemstone)|jet]], and [[pearl]]) may also be used for jewelry and are therefore often considered to be gemstones as well.<ref>{{Cite web |date=2024-01-19 |title=Pearl {{!}} Natural, Cultured & Imitation Gemstones {{!}} Britannica |url=https://www.britannica.com/topic/pearl-gemstone |access-date=2024-03-01 |website=www.britannica.com |language=en}}</ref><ref>{{Cite web |title=Gemopedia - Gemstone Encyclopedia |url=https://www.gemstones.com/gemopedia |access-date=2024-03-01 |website=www.gemstones.com |language=en}}</ref> Most gemstones are hard, but some softer minerals such as [[brazilianite]] may be used in jewelry<ref>{{Cite web |title=Soft Gemstones and Minerals {{!}} Gem5.com |url=https://gem5.com/tag/soft/ |access-date=2024-03-01 |website=gem5.com}}</ref> because of their color or [[Lustre (mineralogy)|luster]] or other physical properties that have [[aesthetic value]]. However, generally speaking, soft minerals are not typically used as gemstones by virtue of their brittleness and lack of durability.<ref>{{Cite web |title=Gemstone Hardness and Wearability |url=https://www.gemsociety.org/article/hardness-and-wearability/}}</ref>

Found all over the world, the industry of coloured gemstones (i.e. anything other than diamonds) is currently estimated at US$1.55 billion as of 2023 and is projected to steadily increase to a value of US$4.46 billion by 2033.<ref>{{Cite web |date=2024-03-01 |title=Colored Gemstones Market: Sales Projection Shows 11.6% CAGR Growth Potential by 2033 – Market Research Blog |url=https://marketresearchblog.org/2024/03/colored-gemstones-market-trends/ |access-date=2024-03-01 |language=en-US}}</ref>

A gem expert is a [[Gemology|gemologist]], a gem maker is called a [[lapidarist]] or [[gemcutter]]; a [[diamond]] cutter is called a [[diamantaire]].

==Characteristics and classification==
[[File:Gem.pebbles.800pix.labelled.jpg|thumb|250px|A [[mineral collecting|collection]] of gemstone [[pebble]]s made by [[tumble finishing|tumbling]] the rough stones, except the ruby and [[tourmaline]], with [[abrasive]] grit inside a rotating barrel. The largest pebble here is {{cvt|40|mm|in}} long.]]

The traditional classification in the West, which goes back to the [[Ancient Greece|ancient Greeks]], begins with a distinction between ''precious'' and ''semi-precious''; similar distinctions are made in other cultures. In modern use, the precious stones are [[emerald]], [[ruby]], [[sapphire]] and [[diamond]], with all other gemstones being semi-precious.<ref>{{cite book|url = https://books.google.com/books?id=crc7ZtRHItgC&pg=PA1 |title =Precious Stones|first =  Max|last = Bauer|page = 2|publisher =Dover Publications|date = 1968|isbn = 9780486219103}}</ref> This distinction reflects the rarity of the respective stones in ancient times, as well as their quality: all are [[translucent]], with fine color in their purest forms (except for the colorless diamond), and very hard with a hardness score of 8 to 10 on the [[Mohs scale of mineral hardness|Mohs scale]].<ref>{{Cite web |title=What are the differences between precious and semi-precious stones? - Information - Leysen - Joaillier since 1855 |url=https://www.leysen.eu/en/news/what-are-the-differences-between-precious-and-semi-precious-stones#:~:text=Precious%20stones%20are%20distinguished%20by,therefore%20called%20semi-precious%20stones. |access-date=2024-02-10 |website=www.leysen.eu}}</ref> Other stones are classified by their color, [[translucency]], and hardness. The traditional distinction does not necessarily reflect modern values; for example, while [[garnet]]s are relatively inexpensive, a green garnet called [[tsavorite]] can be far more valuable than a mid-quality emerald.<ref>Wise, R. W., 2006, ''Secrets of The Gem Trade, The Connoisseur's Guide to Precious Gemstones'', Brunswick House Press, pp. 3–8 {{ISBN|0-9728223-8-0}}</ref> Another traditional term for semi-precious gemstones used in [[art history]] and [[archaeology]] is [[hardstone]]. Use of the terms 'precious' and 'semi-precious' in a commercial context is, arguably, misleading in that it suggests certain stones are more valuable than others when this is not reflected in the actual market value, although it would generally be correct if referring to desirability.

In modern times gemstones are identified by [[gemology|gemologists]], who describe gems and their characteristics using [[technical terminology]] specific to the field of [[gemology]]. The first characteristic a gemologist uses to identify a gemstone is its [[chemical composition]]. For example, [[diamond]]s are made of [[carbon]] ({{chem|C}}) and rubies of [[aluminium oxide]] ({{chem|Al|2|O|3}}). Many gems are crystals which are classified by their [[crystal system]] such as [[Cubic crystal system|cubic]] or [[trigonal]] or [[monoclinic]]. Another term used is [[crystal habit|habit]], the form the gem is usually found in.<ref>{{Cite web |title=Crystal Habits and Forms of Minerals and Gems |url=https://geology.com/minerals/crystal-habit/ |access-date=2024-03-01 |website=geology.com}}</ref> For example, diamonds, which have a cubic crystal system, are often found as [[octahedron]]s.<ref>{{Cite web |title=Diamond |url=https://www.thecanadianencyclopedia.ca/en/article/diamond |access-date=2024-03-01 |website=www.thecanadianencyclopedia.ca |language=en}}</ref>

{{anchor|Gemstone species}}
Gemstones are classified into different ''groups'', ''species'', and ''varieties''.<ref>{{cite book |last1=Hansen |first1=Robin |title=Gemstones: A Concise Reference Guide |date=12 April 2022 |publisher=Princeton University Press |isbn=978-0-691-21448-1 |page=47 |url=https://books.google.com/books?id=QrpFEAAAQBAJ&pg=PA47 |language=en}}</ref><ref>{{cite book |last1=Read |first1=Peter G. |title=Gemmology |date=2005 |publisher=Butterworth-Heinemann |isbn=978-0-7506-6449-3 |page=13 |url=https://books.google.com/books?id=t-OQO3Wk-JsC&pg=PA13 |language=en}}</ref> For example, ruby is the red variety of the species [[corundum]], while any other color of corundum is considered sapphire. Other examples are the [[emerald]] (green), [[Aquamarines|aquamarine]] (blue), [[red beryl]] (red), [[goshenite]] (colorless), [[heliodor]] (yellow), and [[morganite]] (pink), which are all varieties of the mineral species [[beryl]].

Gems are characterized in terms of their color (hue, tone and saturation), optical phenomena, luster, [[refractive index]], [[birefringence]], [[Dispersion (optics)|dispersion]], [[specific gravity]], [[Mohs scale of mineral hardness|hardness]], [[Cleavage (crystal)|cleavage]], and [[fracture]].<ref>{{Cite book |last1=Hurrell |first1=Karen |title=Gemstones: a complete color reference for precious and semiprecious stones of the world |last2=Johnson |first2=Mary L. |date=2017 |publisher=Chartwell Books |isbn=978-0-7858-3498-4 |location=New York}}</ref><ref>{{Cite web |title=Gemstone Identification: How to Identify Gemstones {{!}} Gemstones.com |url=https://www.gemstones.com/articles/gemstone-how-to-identify |access-date=2024-03-01 |website=www.gemstones.com |language=en}}</ref> They may exhibit [[pleochroism]] or [[double refraction]]. They may have [[luminescence]] and a distinctive [[absorption spectrum]]. Gemstones may also be classified in terms of their "water". This is a recognized grading of the gem's luster, transparency, or "brilliance".<ref>AskOxford.com Concise Oxford English dictionary online.{{full citation needed|date=November 2020}}</ref> Very transparent gems are considered "[[first water]]", while "second" or "third water" gems are those of a lesser transparency.<ref>Desirable diamonds: The world's most famous gem. by Sarah Todd.{{full citation needed|date=November 2020}}</ref> Additionally, material or flaws within a stone may be present as [[inclusion (mineral)|inclusions]].<ref>{{Cite web |title=Inclusions in Gemstones |url=http://www.gia.edu/sites/Satellite?c=Page&cid=1495334900680&childpagename=GIA/Page/GGArticleDetail&pagename=GIA/Wrapper&WRAPPERPAGE=GIA/Wrapper |access-date=2024-03-01 |website=www.gia.edu |language=en}}</ref>

==Value==
[[File: Spanish jewellery-Gold and emerald pendant at VAM-01.jpg|thumb|upright|Spanish emerald and gold pendant at [[Victoria and Albert Museum]]]]
[[File:Pendant (cropped).jpg|thumb|upright|Enamelled gold, amethyst, and pearl pendant, about 1880, Pasquale Novissimo (1844–1914), V&A Museum number M.36-1928]]
Gemstones have no universally accepted grading system. Diamonds are graded using a system developed by the [[Gemological Institute of America]] (GIA) in the early 1950s. Historically, all gemstones were graded using the naked eye. The GIA system included a major innovation: the introduction of 10x magnification as the standard for grading clarity. Other gemstones are still graded using the naked eye (assuming 20/20 vision).<ref>Wise, R. W., 2006, ''Secrets of The Gem Trade, The Connoisseur's Guide to Precious Gemstones'', Brunswick House Press, p.36 {{ISBN| 0-9728223-8-0}}</ref>

A [[mnemonic device]], the "four Cs" (color, cut, clarity, and carats), has been introduced to help describe the factors used to grade a diamond. With modification, these categories can be useful in understanding the grading of all gemstones. The four criteria carry different weights depending upon whether they are applied to colored gemstones or to colorless diamonds. In diamonds, the cut is the primary determinant of value, followed by clarity and color. An ideally cut diamond will sparkle, to break down light into its constituent rainbow colors (dispersion), chop it up into bright little pieces (scintillation), and deliver it to the eye (brilliance). In its rough crystalline form, a diamond will do none of these things; it requires proper fashioning and this is called "cut". In gemstones that have color, including colored diamonds, the purity, and beauty of that color is the primary determinant of quality.<ref>Wise, R. W., 2006, ''Secrets of The Gem Trade, The Connoisseur's Guide to Precious Gemstones'', Brunswick House Press, p. 15</ref>

Physical characteristics that make a colored stone valuable are color, clarity to a lesser extent (emeralds will always have a number of inclusions), cut, unusual [[optical phenomena]] within the stone such as color zoning (the uneven distribution of coloring within a gem)<ref>{{Cite web |title=Zoning (Colour Banding) |url=https://www.gemporia.com/en-gb/learning-library/terms/zoning%20(colour%20banding)/ |access-date=2024-03-01 |website=www.gemporia.com |language=en-GB}}</ref> and [[star stone|asteria]] (star effects).

Apart from the more generic and commonly used gemstones such as  from [[diamond]]s, [[Ruby|rubies]], [[sapphire]]s, and [[emerald]]s, [[pearl]]s and [[opal]]<ref name=church>{{cite book | last = Church | first = A.H. | title = Precious Stones considered in their scientific and artistic relations | publisher = His Majesty's Stationery Office, Wyman & Sons | date = 1905|page = 11|chapter = Definition of Precious Stones |url = http://www.farlang.com/gemstones/church-precious-stones/page_011 |archive-url= https://web.archive.org/web/20070929092547/http://www.farlang.com/gemstones/church-precious-stones/page_011 |archive-date= 2007-09-29 | via = Farlang.com}}</ref> have also been defined as precious in the jewellery trade. Up to the discoveries of bulk [[amethyst]] in Brazil in the 19th century, amethyst was considered a "precious stone" as well, going back to ancient Greece. Even in the last century certain stones such as [[Aquamarines|aquamarine]], [[peridot]] and cat's eye ([[cymophane]]) have been popular and hence been regarded as precious, thus reinforcing the notion that a mineral's rarity may have been implicated in its classification as a precious stone and thus contribute to its value.

Today the gemstone trade no longer makes such a distinction.<ref name="WiseSecrets1" /> Many gemstones are used in even the most expensive jewelry, depending on the brand-name of the designer, fashion trends, market supply, treatments, etc. Nevertheless, diamonds, rubies, sapphires, and emeralds still have a reputation that exceeds those of other gemstones.<ref>{{cite web |website = HowStuffWorks.com |url= http://adventure.howstuffworks.com/outdoor-activities/climbing/5-most-precious-stones.htm |title= 5 Most Precious Stones |url-status= live |archive-url= https://web.archive.org/web/20141106143228/http://adventure.howstuffworks.com/outdoor-activities/climbing/5-most-precious-stones.htm |archive-date= 2014-11-06 |date= 2009-11-09 }}</ref>

Rare or unusual gemstones, generally understood to include those gemstones which occur so infrequently in gem quality that they are scarcely known except to connoisseurs, include [[andalusite]], [[axinite]], [[cassiterite]], [[clinohumite]], [[painite]] and [[red beryl]].<ref>{{Cite news |url= http://www.jewellerymonthly.com/what-is-a-gemstone/|title= A complete guide to Gemstones|date= 2015-04-02 |work= Jewellery Monthly|language= en-GB|url-status= live|archive-url= https://web.archive.org/web/20170828191332/http://www.jewellerymonthly.com/what-is-a-gemstone/|archive-date= 2017-08-28}}</ref>

Gemstone pricing and value are governed by factors and characteristics in the quality of the stone. These characteristics include clarity, rarity, freedom from defects, the beauty of the stone, as well as the demand for such stones. There are different pricing influencers for both colored gemstones, and for diamonds. The pricing on colored stones is determined by market supply-and-demand, but diamonds are more intricate.<ref>{{Cite web|title=Pricing of Colored Gemstones {{!}} Joseph Menzie Inc|url=https://menzie.com/colored-gemstone-sales/prices-for-gemstones/|access-date=2021-10-27|language=en-US|archive-date=October 27, 2021|archive-url=https://web.archive.org/web/20211027172652/https://menzie.com/colored-gemstone-sales/prices-for-gemstones/|url-status=live}}</ref>

In the addition to the aesthetic and adorning/ornamental purpose of gemstones, there are many proponents of [[energy medicine]] who also value gemstones on the basis of their alleged [[healing]] powers.<ref>{{cite book |last1=Katz |first1=Michael |url=https://books.google.com/books?id=WUpDAAAACAAJ |title=Gemstone Energy Medicine: Healing Body, Mind and Spirit |date=2005 |publisher=Natural Healing Press |isbn=9780924700248 |access-date=2020-04-06}}</ref>

A gemstone that has been rising in popularity is Cuprian Elbaite Tourmaline which is also called "Paraiba Tourmaline". It was first discovered in the late 1980s in Paraíba, Brazil and later in Mozambique and Nigeria.<ref>{{cite web |url=https://www.gia.edu/gems-gemology/winter-2019-paraiba-tourmaline-geographic-origin-determination |title=Geographic Origin Determination of Paraíba Tourmaline |access-date=March 17, 2022 |archive-date=April 9, 2022 |archive-url=https://web.archive.org/web/20220409023403/https://www.gia.edu/gems-gemology/winter-2019-paraiba-tourmaline-geographic-origin-determination |url-status=live }}</ref> It is famous for its glowing neon blue color. Paraiba Tourmaline has become one of the most popular gemstones in recent times thanks to its color and is considered to be one of the important gemstones after rubies, emeralds, and sapphires according to Gübelin Gemlab. Even though it is a tourmaline, Paraiba Tourmaline is one of the most expensive gemstones.<ref>{{Cite web |title=International Gem Society LLC |url=https://www.gemsociety.org/article/paraiba-tourmaline/}}</ref>

==Grading==
There are a number of laboratories which grade and provide reports on gemstones.<ref name=" WiseSecrets1">Wise, R. W., 2003, ''Secrets of The Gem Trade: The Connoisseur's Guide to Precious Gemstones'', Brunswick House Press, Lenox, Massachusetts.</ref>
* [[Gemological Institute of America]] (GIA), the main provider of education services and diamond grading reports
* [[International Gemological Institute]] (IGI), independent laboratory for grading and evaluation of diamonds, jewelry, and colored stones
* [[Antwerp World Diamond Centre|Hoge Raad Voor Diamant]] (HRD Antwerp), The Diamond High Council, Belgium is one of Europe's oldest laboratories; its main stakeholder is the Antwerp World Diamond Centre
* [[American Gemological Society]] (AGS) is not as widely recognized nor as old as the GIA
* American Gem Trade Laboratory which is part of the American Gem Trade Association (AGTA), a trade organization of jewelers and dealers of colored stones
* American Gemological Laboratories (AGL), owned by Christopher P. Smith
* European Gemological Laboratory (EGL), founded in 1974 by Guy Margel in Belgium
* Gemmological Association of All Japan (GAAJ-ZENHOKYO), Zenhokyo, Japan, active in gemological research
* The Gem and Jewelry Institute of Thailand (Public Organization) or GIT, Thailand's national institute for gemological research and gem testing, Bangkok<ref>{{cite news|url=https://www.bangkokpost.com/learning/international-school/24948/the-gem-and-jewelry-institute-of-thailand-public-organization-|title=The Gem and Jewelry Institute of Thailand (Public Organization)|website=Bangkok Post}}</ref>
* Gemmology Institute of Southern Africa, Africa's premium gem laboratory
* [[Asian Institute of Gemological Sciences]] (AIGS), the oldest gemological institute in South East Asia, involved in gemological education and gem testing
* [[Swiss Gemmological Institute]] (SSEF), founded by Henry Hänni, focusing on colored gemstones and the identification of natural pearls
* Gübelin Gem Lab, the traditional Swiss lab founded by [[Eduard Gübelin]]

Each laboratory has its own methodology to evaluate gemstones. A stone can be called "pink" by one lab while another lab calls it "padparadscha". One lab can conclude a stone is untreated, while another lab might conclude that it is heat-treated.<ref name=" WiseSecrets1" /> To minimize such differences, seven of the most respected labs, AGTA-GTL (New York), CISGEM (Milano), GAAJ-ZENHOKYO (Tokyo), GIA (Carlsbad), GIT (Bangkok), Gübelin (Lucerne) and SSEF (Basel), have established the Laboratory Manual Harmonisation Committee (LMHC), for the standardization of wording reports, promotion of certain analytical methods and interpretation of results. Country of origin has sometimes been difficult to determine, due to the constant discovery of new source locations. Determining a "country of origin" is thus much more difficult than determining other aspects of a gem (such as cut, clarity, etc.).<ref>{{cite web |url=http://www.diamonds.net/news/NewsItem.aspx?ArticleID=17766 |title=Rapaport report of ICA Gemstone Conference in Dubai |publisher=Diamonds.net |date=2007-05-16 |access-date=2010-07-30 |url-status=live |archive-url=https://web.archive.org/web/20110726144914/http://www.diamonds.net/news/NewsItem.aspx?ArticleID=17766 |archive-date=2011-07-26 }}</ref>

Gem dealers are aware of the differences between gem laboratories and will make use of the discrepancies to obtain the best possible certificate.<ref name="WiseSecrets1" />

==Cutting and polishing==
[[File:Diamond cutter. Amsterdam. 2012.jpg|thumb|right|A diamond cutter in [[Amsterdam]]]]

A few gemstones are used as gems in the crystal or other forms in which they are found. Most, however, are cut and polished for usage as jewelry. The two main classifications are as follows:

* Stones cut as smooth, dome-shaped stones called [[cabochon]]s or simply cab. These have been a popular shape since ancient time and is more durable than faceted gems.<ref name=":12">{{Cite web |title=A Guide to Gem Cutting Styles |url=https://www.gemsociety.org/article/gem-cutting-terms/}}</ref>
* Stones which are cut with a [[faceting machine]] by polishing small flat windows called [[facet]]s at regular intervals at exact angles.<ref name=":12"/>

Stones which are opaque or semi-opaque such as [[opal]], [[turquoise]], [[variscite]], etc. are commonly cut as cabochons. These gems are designed to show the stone's color, luster and other surface properties as opposed to internal reflection properties like brilliance.<ref name=":12"/> Grinding wheels and polishing agents are used to grind, shape, and polish the smooth dome shape of the stones.<ref>{{cite book|title = Introduction to Lapidary|first = Pansy D.|last = Kraus|publisher = Krause Publications|date = 2007|isbn = 9780801972669|url-access = registration|url = https://archive.org/details/introductiontola00krau}}</ref>

Gems that are transparent are normally faceted, a method that shows the optical properties of the stone's interior to its best advantage by maximizing reflected light which is perceived by the viewer as sparkle. There are many commonly used shapes for [[diamond cut|faceted stones]]. The facets must be cut at the proper angles, which varies depending on the [[optical]] properties of the gem. If the angles are too steep or too shallow, the light will pass through and not be reflected back toward the viewer. The faceting machine is used to hold the stone onto a flat lap for cutting and polishing the flat facets.<ref>{{cite book|title = Faceting For Amateurs |first1= Glenn|last1= Vargas|first2= Martha|last2= Vargas|date = 2002 |publisher= G. & M. Vargas|isbn = 9780917646096}}</ref> Rarely, some cutters use special curved laps to cut and polish curved facets.

==Colors==
[[File: Aurora Pyramid of Hope.jpg|thumb|Nearly 300 variations of diamond color exhibited at [[Aurora Pyramid of Hope|the Aurora display]] at the Natural History Museum in London]]
[[File:Semiprecious stones in a piece of jewellery.jpeg|thumb|A variety of semiprecious stones in a piece of jewellery]]
The color of any material is due to the nature of light itself. Daylight, often called white light, is all of the colors of the spectrum combined. When light strikes a material, most of the light is absorbed while a smaller amount of a particular frequency or wavelength is reflected. The part that is reflected reaches the eye as the perceived color.<ref>{{Cite web |title=Seeing Color |url=https://www.amnh.org/explore/ology/brain/seeing-color#:~:text=Light%20travels%20into%20the%20eye,Cone%20cells%20help%20detect%20colors.}}</ref> A ruby appears red because it absorbs all other colors of white light while reflecting red.

A material which is mostly the same can exhibit different colors. For example, ruby and sapphire have the same primary chemical composition (both are [[corundum]])<ref>{{Cite web |title=Ruby and Sapphire: Gems of the Mineral Corundum |url=https://geology.com/gemstones/ruby-and-sapphire/ |access-date=2024-03-01 |website=geology.com}}</ref> but exhibit different colors because of impurities which absorb and reflect different wavelengths of light depending on their individual compositions. Even the same named gemstone can occur in many different colors: sapphires show different shades of blue and pink and "fancy sapphires" exhibit a whole range of other colors from yellow to orange-pink, the latter called "[[Padparadscha|padparadscha sapphire]]".<ref>{{Cite news|url=https://www.thenaturalsapphirecompany.com/blog/padparadscha-sapphires-a-buying-guide|title=Padparadscha Sapphires: 10 Tips On Judging The Rare Gem|date=2015-04-06|work=The Natural Sapphire Company Blog|access-date=2018-01-19|language=en-US|archive-date=January 19, 2018|archive-url=https://web.archive.org/web/20180119235335/https://www.thenaturalsapphirecompany.com/blog/padparadscha-sapphires-a-buying-guide|url-status=live}}</ref>

This difference in color is based on the atomic structure of the stone. Although the different stones formally have the same chemical composition and structure, they are not exactly the same. Every now and then an atom is replaced by a completely different atom, sometimes as few as one in a million atoms. These so-called [[impurities]] are sufficient to absorb certain colors and leave the other colors unaffected. For example, [[beryl]], which is colorless in its pure mineral form, becomes emerald with chromium impurities. If [[manganese]] is added instead of [[chromium]], beryl becomes pink [[morganite]]. With iron, it becomes [[Aquamarines|aquamarine.]]Some gemstone treatments make use of the fact that these impurities can be "manipulated", thus changing the color of the gem.

==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 the innovation of modern-day tools, thousands of years ago, people were recorded to use a variety of techniques to treat and enhance gemstones. Some of the earliest methods of gemstone treatment date back to the Minoan Age, for example foiling, which is where 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 |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" />

== Socioeconomic issues in the gemstone industry ==
The socio-economic dynamics of the gemstone industry are shaped by market forces and consumer preferences and typically go undiscussed. Changes in demand and prices can significantly affect the livelihoods of those involved in gemstone mining and trade, particularly in [[Developing country|developing countries]] where the industry serves as a crucial source of income.<ref name=":2">{{Cite report |url=https://www.jstor.org/stable/resrep02665|title=Artisanal and small-scale mining and agriculture: Exploring their links in rural sub-Saharan Africa|last=Hilson |first=Gavin|date=2016 |publisher=International Institute for Environment and Development}}</ref>

A situation that arises as a result of this is the exploitation of [[natural resource]]s and labor within gemstone mining operations. Many mines, particularly in developing countries, face challenges such as inadequate safety measures, low wages, and poor working conditions.<ref name=":2" /> [[Miner]]s, often from disadvantaged backgrounds, endure hazardous working conditions and receive meager wages, contributing to cycles of [[poverty]] and exploitation.<ref>{{Cite journal |last=Fisher|first=Eleanor |date=July 2007|title=Occupying the Margins: Labour Integration and Social Exclusion in Artisanal Mining in Tanzania |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1467-7660.2007.00431.x |journal=Development and Change |language=en|volume=38|issue=4 |pages=735–760|doi=10.1111/j.1467-7660.2007.00431.x|issn=0012-155X}}</ref> Gemstone [[mining]] operations are frequently conducted in remote or underdeveloped areas, lacking proper infrastructure and access to essential services such as healthcare and education. This further contributes to the pre-existing [[Socioeconomic status|socio-economic disparities]] and obstructs community development such that the benefits of gemstone extraction may not adequately reach those directly involved in the process.<ref>{{Cite journal |last1=Hinton|first1=Jennifer J |last2=Veiga|first2=Marcello M |last3=Veiga|first3=A.Tadeu C |date=March 2003|title=Clean artisanal gold mining: a utopian approach? |url=https://doi.org/10.1016/S0959-6526(02)00031-8|journal=Journal of Cleaner Production|volume=11 |issue=2|pages=99–115 |doi=10.1016/s0959-6526(02)00031-8 |bibcode=2003JCPro..11...99H |issn=0959-6526}}</ref>

Another such issue revolves around [[environmental degradation]] resulting from mining activities. Environmental degradation can pose long-term threats to ecosystems and biodiversity, further worsening the socio-economic state in affected regions.<ref>{{Cite book |last=Hentschel|first=Thomas |title=Global Report on Artisanal & Small-Scale Mining |publisher=Mining, Minerals and Sustainable Development|year=2002 |isbn=9978-40-971-8}}</ref> Unregulated mining practices often result in [[deforestation]], [[soil erosion]], and [[Water pollution|water contamination]] thus threatening [[ecosystem]]s and [[biodiversity]].<ref>{{Cite journal|last1=Takam Tiamgne |first1=Xavier|last2=Kalaba |first2=Felix K.|last3=Nyirenda |first3=Vincent R.|date=September 2022|title=Mining and socio-ecological systems: A systematic review of Sub-Saharan Africa |url=https://doi.org/10.1016/j.resourpol.2022.102947 |journal=Resources Policy |volume=78|pages=102947 |doi=10.1016/j.resourpol.2022.102947|bibcode=2022RePol..7802947T |issn=0301-4207}}</ref> Unregulated mining activity can also cause depletion of natural resources, thus diminishing the prospects for [[sustainable development]].<ref>{{Cite journal |last1=Dissanayake|first1=C. B. |last2=Rupasinghe|first2=M. S. |date=October 1996 |title=Environmental impact of mining, erosion and sedimentation in Sri Lanka |url=http://www.tandfonline.com/doi/abs/10.1080/00207239608711069 |journal=International Journal of Environmental Studies|language=en |volume=51|issue=1|pages=35–50 |doi=10.1080/00207239608711069 |bibcode=1996IJEnS..51...35D |issn=0020-7233}}</ref> The environmental impact of gemstone mining not only poses a threat to ecosystems but also undermines the long-term viability of the industry by diminishing the quality and quantity of available resources.

Furthermore, the gemstone industry is also susceptible to issues related to transparency and ethics, which impact both producers and consumers. The lack of standardized certification processes and the prevalence of illicit practices undermine market integrity and trust.<ref>{{Cite web |last=Harrington|first=Alexandra R.|title=Faceting the Future: The Need for and Proposal of the Adoption of a Kimberley Process-Styled Legitimacy Certification System for the Global Gemstone Market |url=https://www.researchgate.net/publication/228264264 |website=Research Gate}}</ref> The lack of transparency and accountability in the supply chain aggravates pre-existing inequalities, as middlemen and corporations often capture a disproportionate share of the profits. As a result, the unequal distribution of profits along the [[supply chain]] does little to improve socio-economic inequalities, particularly in regions where gemstones are mined.

Addressing these socio-economic challenges requires intensive effort from various stakeholders, including governments, industry executives, and society, to promote sustainable practices and ensure equitable outcomes for all involved parties. Implementing and enforcing regulations to ensure fair labor practices, environmental sustainability, and ethical sourcing is essential. Additionally, investing in community development projects, such as education and healthcare initiatives, can help alleviate poverty and empower marginalized communities dependent on the gemstone industry. Collaboration across sectors is crucial for fostering a more equitable and sustainable gemstone trade that benefits both producers and consumers while respecting human rights and environmental integrity.

==Synthetic and artificial gemstones==
Synthetic gemstones are distinct from imitation or simulated gems.

Synthetic gems are physically, optically, and chemically identical to the natural stone, but are created in a laboratory.<ref>{{cite book |url=https://books.google.com/books?id=HrESAQAAMAAJ |title=Jewelers' circular-keystone: JCK |date=1994 |publisher=Chilton Company |language=en}}{{full citation needed|date=November 2020}}</ref> Imitation or simulated stones are chemically different from the natural stone, but may appear quite similar to it; they can be more easily manufactured synthetic gemstones of a different mineral ([[spinel#Synthetic spinel|spinel]]), glass, plastic, resins, or other compounds.

Examples of simulated or imitation stones include [[cubic zirconia]], composed of [[zirconium]] oxide, synthetic [[moissanite]], and uncolored, synthetic [[corundum#Synthetic corundum|corundum]] or [[spinel#Synthetic spinel|spinel]]s; all of which are [[diamond simulants]]. The simulants imitate the look and color of the real stone but possess neither their chemical nor physical characteristics. In general, all are less [[Mohs scale of mineral hardness|hard]] than diamond. Moissanite actually has a ''higher'' refractive index than diamond, and when presented beside an equivalently sized and cut diamond will show more "fire".

Cultured, synthetic, or "lab-created" gemstones are not imitations: The bulk mineral and trace coloring elements are the same in both. For example, [[diamond]]s, [[Ruby|rubies]], [[sapphire]]s, and [[emerald]]s have been manufactured in labs that possess chemical and physical characteristics identical to the naturally occurring variety. Synthetic (lab created) [[corundum#Synthetic corundum|corundum]], including ruby and sapphire, is very common and costs much less than the natural stones. Small [[synthetic diamond]]s have been manufactured in large quantities as industrial [[abrasive]]s, although larger gem-quality synthetic diamonds are becoming available in multiple carats.<ref>{{cite web |title=New process promises bigger, better diamond crystals |url=http://carnegiescience.edu/news/new_process_promises_bigger_better_diamond_crystals |publisher=Carnegie Institution for Science |access-date=7 January 2011 |url-status=live |archive-url=https://web.archive.org/web/20101201005848/http://carnegiescience.edu/news/new_process_promises_bigger_better_diamond_crystals |archive-date=1 December 2010}}</ref>

Whether a gemstone is a natural stone or synthetic, the chemical, physical, and optical characteristics are the same: They are composed of the same [[mineral]] and are colored by the same trace materials, have the same [[Mohs scale of mineral hardness|hardness]] and [[density]] and [[strength of materials|strength]], and show the same [[spectroscopy|color spectrum]], [[refractive index]], and [[birefringence]] (if any). Lab-created stones tend to have a more vivid color since impurities common in natural stones are not present in the synthetic stone. Synthetics are made free of common naturally occurring impurities that reduce gem clarity or color unless intentionally added in order to provide a more drab, natural appearance, or to deceive an assayer.{{citation needed|date=May 2012}} On the other hand, synthetics often show flaws not seen in natural stones, such as minute particles of corroded metal from lab trays used during synthesis.{{citation needed|date=April 2024}}

=== Types ===
Some gemstones are more difficult to synthesize than others and not all stones are commercially viable to attempt to synthesize. These are the most common on the market currently.<ref name="Weldon">{{cite web |author=Weldon, R. |title=An Introduction to Synthetic Gem Materials |access-date=2023-04-14 |url=http://www.gingermeekallen.com/wp-content/uploads/2014/09/An-Introduction-to-Synthetic-Gem-Materials.pdf |archive-date=April 15, 2023 |archive-url=https://web.archive.org/web/20230415073916/http://www.gingermeekallen.com/wp-content/uploads/2014/09/An-Introduction-to-Synthetic-Gem-Materials.pdf |url-status=live }}</ref>

==== Synthetic corundum ====
Synthetic corundum includes ruby (red variation) and sapphire (other color variations), both of which are considered highly desired and valued.<ref name="Weldon"/> Ruby was the first gemstone to be synthesized by Auguste Verneuil with his development of the flame-fusion process in 1902.<ref>{{Cite journal |last=Shigley |first=James |date=2000 |title=Treated and synthetic gem materials |jstor=24104849 |journal=Current Science |volume=79 |issue=11 |pages=1566–1571}}</ref> Synthetic corundum continues to be made typically by flame-fusion as it is most cost-effective, but can also be produced through flux growth and hydrothermal growth.<ref>{{Cite journal |last=Elwell |first=Dennis |date=1981 |editor-last=Nassau |editor-first=Kurt |title=Synthetic Gemstones |url=https://www.jstor.org/stable/1685235 |journal=Science |volume=211 |issue=4487 |pages=1156 |doi=10.1126/science.211.4487.1156.a |jstor=1685235 |pmid=17755153 |s2cid=239860410 |issn=0036-8075 |access-date=April 15, 2023 |archive-date=April 15, 2023 |archive-url=https://web.archive.org/web/20230415034649/https://www.jstor.org/stable/1685235 |url-status=live }}</ref>

==== Synthetic beryls ====
The most common synthesized beryl is emerald (green). Yellow, red and blue beryls are possible but much more rare. Synthetic emerald became possible with the development of the flux growth process and is produced in this way and well as hydrothermal growth.<ref name="Lefever-1982">{{Cite web |last=Lefever |first=R |date=1982 |title=Synthetic emerald |website=pubs.geoscienceworld.org |url=https://pubs.geoscienceworld.org/msa/ammin/article/47/11-12/1450/542016/Synthetic-emerald |access-date=2023-03-15}}</ref>

==== Synthetic quartz ====
Types of synthetic quartz include citrine, rose quartz, and amethyst. Natural occurring quartz is not rare, but is nevertheless synthetically produced as it has practical application outside of aesthetic purposes. Quartz generates an electric current when under pressure and is used in watches, clocks, and oscillators.<ref>{{Cite journal |last1=Hervey |first1=P. R. |last2=Foise |first2=J. W. |date=2001-02-01 |title=Synthetic quartz crystal — A review |url=https://doi.org/10.1007/BF03402862 |journal=Mining, Metallurgy & Exploration |language=en |volume=18 |issue=1 |pages=1–4 |doi=10.1007/BF03402862 |bibcode=2001MMExp..18....1H |s2cid=140031745 |issn=2524-3470}}</ref>

==== Synthetic spinel ====
Synthetic spinel was first produced by accident.{{clarification needed|date=August 2023}} It can be created in any color making it popular to simulate various natural gemstones. It is created through flux growth and hydrothermal growth.<ref name="Weldon"/>

=== Creation process ===
There are two main categories for creation of these minerals: melt or solution processes.<ref name="Weldon"/>

==== Verneuil flame fusion process (melt process) ====
[[File:Verneuil process diagram.svg|thumb|Verneuil furnace]]
The flame fusion process was the first process used which successfully created large quantities of synthetic gemstones to be sold on the market.<ref name="Scheel-2000">{{Cite journal |last=Scheel |first=Hans J |date=2000-04-01 |title=Historical aspects of crystal growth technology |url=https://www.sciencedirect.com/science/article/pii/S0022024899007800 |journal=Journal of Crystal Growth |language=en |volume=211 |issue=1 |pages=1–12 |doi=10.1016/S0022-0248(99)00780-0 |bibcode=2000JCrGr.211....1S |issn=0022-0248 |access-date=April 15, 2023 |archive-date=April 15, 2023 |archive-url=https://web.archive.org/web/20230415031315/https://www.sciencedirect.com/science/article/pii/S0022024899007800 |url-status=live }}</ref> This remains the most cost effective and common method of creating corundums today.

The flame fusion process is completed in a Verneuil furnace. The furnace consists of an inverted blowpipe burner which produces an extremely hot oxyhydrogen flame, a powder dispenser, and a ceramic pedestal.<ref name="Read-1999">{{Cite book |last=Read |first=Peter G. |title=Gemmology |date=1999 |publisher=Butterworth-Heinemann |isbn=0-7506-4411-7 |oclc=807757024}}</ref> A chemical powder which corresponds to the desired gemstone is passed through this flames. This melts the ingredients which drop on to a plate and solidify into a crystal called a ''boule''.<ref name="Read-1999"/> For corundum the flame must be 2000&nbsp;°C. This process takes hours and yields a crystal with the same properties as its natural counterpart.

To produce corundum, a pure aluminium powder is used with different additives to achieve different colors.<ref name="Read-1999"/>

* Chromic oxide for ruby
* Iron and titanium oxide for blue sapphire
* Nickel oxide for yellow sapphire
* Nickel, chromium and iron for orange sapphire
* Manganese for pink sapphire
* Copper for blue-green sapphire
* Cobalt for dark blue sapphire

==== Czochralski process (melt process) ====
In 1918 this process was developed by J. Czocharalski<ref name="Read-1999"/> and is also referred to as the "crystal pulling" method. In this process, the required gemstone materials are added to a crucible. A seed stone is placed into the melt in the crucible. As the gem begins to crystallize on the seed, the seed is pulled away and the gem continues to grow.<ref name="Weldon"/> This is used for corundum but is currently the least popular method.<ref name="Scheel-2000"/>

==== Flux growth (solution process) ====
The flux growth process was the first process able to synthesize emerald.<ref name="Lefever-1982"/> Flux growth begins with a crucible which can withstand high heat; either graphite or platinum which is filled with a molten liquid referred to as flux.<ref name="Scheel-2003">{{Cite book |last=Scheel |first=Hans |title=Crystal Growth Technology |publisher=John Wiley & Sons |year=2003 |isbn=9780470871683}}</ref> The specific gem ingredients are added and dissolved in this fluid and recrystallize to form the desired gemstone.This is a longer process compared to the flame fusion process and can take two months up to a year depending on the desired final size.<ref name="Arem">{{Cite web |last=Arem |first=Joel |title=Understanding Gem Synthetics, Treatments, And Imitations, Part 4: Synthetic Gemstone Guide |website=International Gem Society |url=https://www.gemsociety.org/article/understanding-gem-synthetics-treatments-imitations-part-4-synthetic-gemstone-guide/ |access-date=March 30, 2023 |archive-date=March 22, 2023 |archive-url=https://web.archive.org/web/20230322211822/https://www.gemsociety.org/article/understanding-gem-synthetics-treatments-imitations-part-4-synthetic-gemstone-guide/ |url-status=live }}</ref>

==== Hydrothermal growth (solution process) ====
The hydrothermal growth process attempts to imitate the natural growth process of minerals. The required gem materials are sealed in a container of water and placed under extreme pressure. The water is heated beyond its boiling point which allows normally insoluble materials to dissolve. As more material cannot be added once the container is sealed, in order to create a larger gem the process would begin with a "seed" stone from a previous batch which the new material will crystallize on. This process takes a few weeks to complete.

=== Characteristics ===
Synthetic gemstones share chemical and physical properties with natural gemstones, but there are some slight differences that can be used to discern synthetic from natural.<ref>{{Cite journal |last=Jayaraman |first=A |date= December 28, 2023|title=A brief overview of gem materials: Natural and synthetic |url=https://www.jstor.org/stable/24104848 |journal=Current Science |volume=79 |issue=11 |pages=1555–1565 |jstor=24104848 |via= |archive-date= April 15, 2023 |archive-url=https://web.archive.org/web/20230415034735/https://www.jstor.org/stable/24104848?searchText=&searchUri=&ab_segments=&searchKey=&refreqid=fastly-default:03cfdfcd0fc6ba4823dbdf226c8f4575 |url-status=live }}</ref> These differences are slight and often require microscopy as a tool to distinguish differences. Undetectable synthetics pose a threat to the market if they are able to be sold as rare natural gemstones.{{citation needed|date=April 2024}} Because of this there are certain characteristic gemologists look for. Each crystal is characteristic to the environment and growth process under which it was created.
[[File:Golden Apatite.jpg|thumb|Visible banding in an [[apatite]] gemstone]]
Gemstones created from the flame-fusion process may have

* small air bubbles which were trapped inside the boule during formation process
* visible banding from formation of the boule
* chatter marks which on the surface which appear crack like which are caused from damage during polishing of the gemstone

Gemstones created from flux melt process may have

* small cavities which are filled with flux solution
* inclusions in the gemstone from crucible used<ref name="Li-2001">{{Cite journal |last=Li |first=Zhaolin |date=2001-12-01 |title=Study on inclusions in natural and synthetic gems |url=https://doi.org/10.1007/BF03166857 |journal=Chinese Journal of Geochemistry |language=en |volume=20 |issue=4 |pages=324–332 |doi=10.1007/BF03166857 |s2cid=129031255 |issn=1993-0364}}</ref>

Gemstones created from hydrothermal growth may have

* inclusions from container used<ref name="Li-2001" />

=== History ===
[[File:Auguste Victor Louis Verneuil.jpg|thumb|upright|left|Auguste Verneuil – creator of flame-fusion process 1902]]
Prior to development of synthesising processes the alternatives on the market to natural gemstones were imitations or fake. In 1837, the first successful synthesis of ruby occurred.<ref name="Scheel-2000"/> French chemist Marc Gaudin managed to produce small crystals of ruby from melting together potassium aluminium sulphate and potassium chromate through what would later be known as the flux melt process.<ref name="Read-1999"/> Following this, another French chemist Fremy was able to grow large quantities of small ruby crystals using a lead flux.<ref name="Scheel-2003"/>

A few years later an alternative to flux melt was developed which led to the introduction of what was labeled "reconstructed ruby" to the market. Reconstructed ruby was sold as a process which produced larger rubies from melting together bits of natural ruby.<ref name="Arem"/> In later attempts to recreate this process it was found to not be possible and is believed reconstructed rubies were most likely created using a multi-step method of melting of ruby powder.<ref name="Read-1999"/>

Auguste Verneuil, a student of Fremy, went on to develop flame-fusion as an alternative to the flux-melt method. He developed large furnaces which were able to produce large quantities of corundums more efficiently and shifted the gemstone market dramatically.<ref>{{Cite journal |last=Nassau |first=Kurt |date=1990 |title=Synthetic Gem Materials in the 1980s |url=https://www.gia.edu/doc/Synthetic-Gem-Materials-in-the-1980s.pdf |journal=Gems & Gemology |volume=26 |issue=1 |pages=50–63 |doi=10.5741/GEMS.26.1.50 |access-date=April 15, 2023 |archive-date=November 1, 2021 |archive-url=https://web.archive.org/web/20211101192418/https://www.gia.edu/doc/Synthetic-Gem-Materials-in-the-1980s.pdf |url-status=live }}</ref> This process is still used today and the furnaces have not changed much from the original design.<ref>{{Cite journal |last=Harris |first=Daniel C. |editor-first1=Randal W. |editor-last1=Tustison |date=2003-09-26 |title=A peek into the history of sapphire crystal growth |url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/5078/0000/A-peek-into-the-history-of-sapphire-crystal-growth/10.1117/12.501428.full |journal=Window and Dome Technologies VIII |publisher=SPIE |volume=5078 |pages=1–11 |doi=10.1117/12.501428|bibcode=2003SPIE.5078....1H |s2cid=109528895 }}</ref> World production of corundum using this method reaches 1000 million carats a year.

==List of rare gemstones==
* [[Painite]] was discovered in 1956 in Ohngaing in Myanmar. The mineral was named in honor of the British gemologist Arthur Charles Davy Pain. At one point it was considered the rarest mineral on Earth.{{sfn|Hansen|2022|p=206}}
* [[Tanzanite]] was discovered in 1967 in Northern Tanzania. With its supply possibly declining in the next 30 years, this gemstone is considered to be more rare than a diamond. This type of gemstone receives its vibrant blue from being heated.<ref name="Spruce">{{Cite web |title=10 Gems Rarer and More Valuable Than Diamonds |url=https://www.thesprucecrafts.com/most-valuable-gemstones-in-the-world-4105417 |access-date=2023-03-31 |website=The Spruce Crafts |language=en |archive-date=March 31, 2023 |archive-url=https://web.archive.org/web/20230331215058/https://www.thesprucecrafts.com/most-valuable-gemstones-in-the-world-4105417 |url-status=live }}</ref>
* [[Hibonite]] was discovered in 1956 in Madagascar. It was named after the discoverer, French geologist Paul Hibon. Gem quality hibonite has been found only in Myanmar.<ref>{{cite journal|url=https://www.gia.edu/doc/Hibonite-a-New-Gem-Mineral.pdf |title=Hibonite: A New Gem Mineral |archive-url=https://web.archive.org/web/20171213082143/https://www.gia.edu/doc/Hibonite-a-New-Gem-Mineral.pdf |archive-date=2017-12-13 |url-status=live |journal=Gems & Gemology |volume=46 |number=2 |pages=135–138 |date=Summer 2010 |first1=Thomas |last1=Hainschwang |first2=Franck |last2=Notari |first3=Laurent |last3=Massi|first4=Thomas |last4=Armbruster |first5=Benjamin |last5=Rondeau |first6=Emmanuel |last6=Fritsch |first7=Mariko |last7=Nagashima |doi=10.5741/GEMS.46.2.135}}</ref>
[[File:RedBeryl-G-EmpireTheWorldOfGems (cropped).jpg|thumb|Red Beryl - discovered in 1940]]
* [[Red beryl]] or bixbite was discovered in an area near Beaver, Utah in 1904 and named after the American mineralogist Maynard Bixby.
* [[Jeremejevite]] was discovered in 1883 in Russia and named after its discoverer, Pawel Wladimirowich Jeremejew (1830–1899).
* [[Chambersite]] was discovered in 1957 in Chambers County, Texas, US, and named after the deposit's location.
* [[Taaffeite]] was discovered in 1945. It was named after the discoverer, the Irish gemologist Count Edward Charles Richard Taaffe.
* [[Musgravite]] was discovered in 1967 in the Musgrave Mountains in South Australia and named for the location.
[[File:Black opal (Stayish Mine, Wollo Province, Ethiopia) 6 (23226115484).jpg|thumb|Black Opal – the rarest type of opal]]
* [[Black opal]] is directly mined in New South Wales, Australia, making it the rarest type of opal. Having a darker composition, this gemstone can be in a variety of colours.<ref name="Spruce" /> 
* [[Grandidierite]] was discovered by Antoine François Alfred Lacroix (1863–1948) in 1902 in Tuléar Province, Madagascar. It was named in honor of the French naturalist and explorer Alfred Grandidier (1836–1912).
* [[Poudretteite]] was discovered in 1965 at the Poudrette Quarry in Canada and named after the quarry's owners and operators, the Poudrette family.
* [[Serendibite]] was discovered in Sri Lanka by Sunil Palitha Gunasekera in 1902 and named after Serendib, the old Arabic name for Sri Lanka.
* [[Zektzerite]] was discovered by Bart Cannon in 1968 on Kangaroo Ridge near Washington Pass in Okanogan County, Washington, USA. The mineral was named in honor of mathematician and geologist Jack Zektzer, who presented the material for study in 1976.

==In popular culture==
French singer-songwriter [[Nolwenn Leroy]] was inspired by the gemstones for her 2017 album ''Gemme'' (meaning gemstone in French) and the single of the same name.<ref>{{in lang|fr}} [https://www.rtl.fr/culture/musique/video-nolwenn-leroy-lumineuse-et-enceinte-dans-le-clip-de-gemme-7789410563 "Vidéo – Nolwenn Leroy lumineuse et enceinte dans le clip de Gemme"]. RTL. 19 July 2017.</ref>

[[Land of the Lustrous]] is a Japanese manga and anime series whose main characters are depicted as humanoid jewels.<ref>{{Cite web |title=Houseki no Kuni |url=https://myanimelist.net/manga/44489/Houseki_no_Kuni |access-date=2024-11-15 |website=MyAnimeList.net |language=en}}</ref><ref>{{Cite AV media |url=https://myanimelist.net/anime/35557/Houseki_no_Kuni |title=Houseki no Kuni |language=en |access-date=2024-11-15 |via=myanimelist.net}}</ref>

[[Steven Universe]] is an American animated television series whose main characters are magical gemstones who project themselves as feminine humanoids.<ref>{{Citation |title=Steven Universe |date=2013-07-27 |type=Animation, Short, Action |url=https://www.imdb.com/title/tt3061046/ |access-date=2024-11-15 |others=Zach Callison, Deedee Magno, Michaela Dietz |publisher=Cartoon Network Studios}}</ref>

==See also==
* [[Assembled gem]]
* [[Gemology]]
* [[List of gemstones by species]]
* [[List of individual gemstones]]
* [[List of diamonds]]
* [[List of emeralds by size]]
* [[List of sapphires by size]]
*[[Luminous gemstones]]

== References ==
{{Reflist|30em}}

==External links==
* {{Wikiquote-inline}}
* {{Commons category-inline|Gemstones}}
* {{Wiktionary-inline|gemstones}}
* {{wikivoyage inline}}
{{Gemstones}}
{{Jewellery}}
{{Authority control}}

[[Category:Gemstones| ]]
[[Category:Jewellery components]]
[[Category:Materials]]
[[Category:Mineralogy]]
[[Category:Minerals|*]]
[[Category:Stone objects]]