Editing Garnet (section)

==Garnet group end member species==

===Pyralspite garnets – aluminium in ''Y'' site===
*[[Almandine]]: Fe<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>
*[[Pyrope]]: Mg<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>
*[[Spessartine]]: [[manganese|Mn]]<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>

====Almandine====
[[File:Almandine.jpeg|thumb|Almandine in metamorphic rock]]

Almandine, sometimes incorrectly called almandite, is the modern gem known as [[Carbuncle (gemstone)|carbuncle]] (though originally almost any red gemstone was known by this name).<ref name="lytvynov">{{cite journal |last1=Lytvynov |first1=L. A. |title=On the words used as names for ruby and sapphire |journal=Functional Materials |date=2011 |volume=18 |issue=2 |pages=274–277 |url=http://dspace.nbuv.gov.ua/bitstream/handle/123456789/135445/21-Lytvynov.pdf?sequence=1 |access-date=7 December 2020}}</ref> The term "carbuncle" is derived from the [[Latin]] meaning "live coal" or burning charcoal. The name ''Almandine'' is a corruption of [[Alabanda]], a region in [[Asia Minor]] where these stones were cut in ancient times.  Chemically, almandine is an iron-aluminium garnet with the formula Fe<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>; the deep red transparent stones are often called precious garnet and are used as gemstones (being the most common of the gem garnets).<ref>{{cite journal |last1=Jensen |first1=David E. |title=The Garnet Group |journal=Rocks & Minerals |date=November 1975 |volume=50 |issue=10 |pages=584–587 |doi=10.1080/00357529.1975.11767172|bibcode=1975RoMin..50..584J }}</ref> Almandine occurs in [[metamorphic rock]]s like [[mica]] [[schist]]s, associated with minerals such as [[staurolite]], [[kyanite]], [[andalusite]], and others.{{sfn|Nesse|2000|pp=312,320}} Almandine has nicknames of Oriental garnet,<ref>{{cite book |date=2009 |pages=19–20 |doi=10.1007/978-3-540-72816-0_532|isbn=978-3-540-72795-8 |chapter=Almandine |title=Dictionary of Gems and Gemology }}</ref> almandine ruby, and carbuncle.<ref name="lytvynov"/>

====Pyrope====
Pyrope (from the Greek ''pyrōpós'' meaning "firelike")<ref name="Klein-1993" /> is red in color and chemically an aluminium [[silicate]] with the formula Mg<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>, though the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to black. Pyrope and spessartine gemstones have been recovered from the Sloan diamondiferous [[kimberlite]]s in [[Colorado]], from the Bishop Conglomerate and in a [[Tertiary|Tertiary age]] [[lamprophyre]] at Cedar Mountain in [[Wyoming]].<ref>{{cite book|last=Hausel|first=W. Dan|title=Gemstones and Other Unique Rocks and Minerals of Wyoming – Field Guide for Collectors|year=2000|publisher=Wyoming Geological Survey|location=Laramie, Wyoming|pages=268 p}}</ref>

A variety of pyrope from [[Macon County, North Carolina|Macon County]], [[North Carolina]] is a violet-red shade and has been called ''rhodolite'', Greek for "rose". In chemical composition it may be considered as essentially an isomorphous mixture of pyrope and almandine, in the proportion of two parts pyrope to one part almandine.<ref name="schlegel">{{cite journal |last1=Schlegel |first1=Dorothy M. |title=Gem stones of the United States |journal=U.S. Geological Survey Bulletin |date=1957 |volume=1042-G |page=203 |doi=10.3133/b1042G|doi-access=free |bibcode=1957usgs.rept....3S }}</ref> Pyrope has tradenames some of which are [[misnomer]]s; ''Cape ruby'', ''Arizona ruby'', ''California ruby'', ''Rocky Mountain ruby'', and ''Bohemian ruby'' from the [[Czech Republic]].<ref name="lytvynov"/>

[[Pyrope]] is an indicator mineral for high-pressure rocks. [[Earth's mantle|Mantle]]-derived rocks ([[peridotite]]s and [[eclogite]]s) commonly contain a pyrope variety.{{sfn|Klein|Hurlbut|1993|pp=453, 587–588}}

====Spessartine====
[[File:Espessartita.jpeg|thumb|right|Spessartine (the reddish mineral)]]

Spessartine or spessartite is manganese aluminium garnet, Mn<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>. Its name is derived from [[Spessart]] in [[Bavaria]].<ref name="Klein-1993"/> It occurs most often in [[skarn]]s,<ref name="Klein-1993"/> [[granite]] [[pegmatite]] and allied rock types,{{sfn|Nesse|2000|p=312}} and in certain low grade metamorphic [[phyllite]]s. Spessartine of an [[orange (colour)|orange]]-yellow is found in Madagascar.<ref>{{cite journal |last1=Schmetzer |first1=Karl |last2=Bernhardt |first2=Heinz-Jürgen |title=Gem-quality spessartine-grossular garnet of intermediate composition from Madagascar |journal=Journal of Gemmology |date=2002 |volume=28 |issue=4 |pages=235–239|doi=10.15506/JoG.2002.28.4.235 }}</ref> Violet-red spessartines are found in [[rhyolite]]s in [[Colorado]]<ref name="schlegel"/> {{citation needed span|date=December 2012|and [[Maine]].}}

====Pyrope–spessartine (blue garnet or color-change garnet)====
Blue pyrope–spessartine garnets were discovered in the late&nbsp;1990s in Bekily, [[Madagascar]]. This type has also been found in parts of the [[United States]], [[Russia]], [[Kenya]], [[Tanzania]], and [[Turkey]]. It changes color from blue-green to purple depending on the [[color temperature]] of viewing light, as a result of the relatively high amounts of [[vanadium]] (about 1 wt.% V<sub>2</sub>O<sub>3</sub>).<ref name="blue">{{cite journal |last1=Schmetzer |first1=Karl |last2=Bernhardt |first2=Heinz-Jürgen |title=Garnets from Madagascar with a color change from blue-green to purple |journal=Gems & Gemology |date=Winter 1999 |volume=35 |issue=4 |pages=196–201 |doi=10.5741/GEMS.35.4.196 |url=https://www.gia.edu/doc/WN99A4.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.gia.edu/doc/WN99A4.pdf |archive-date=2022-10-09 |url-status=live |access-date=7 December 2020|doi-access=free }}</ref>

Other varieties of color-changing garnets exist. In daylight, their color ranges from shades of green, beige, brown, gray, and blue, but in incandescent light, they appear a reddish or purplish/pink color.<ref>{{Cite web |title=Color Change Garnet Value, Price, and Jewelry Information - Gem Society |url=https://www.gemsociety.org/article/color-change-garnet/ |access-date=2022-10-13 |website=International Gem Society |language=en-US}}</ref>

This is the rarest type of garnet. Because of its color-changing quality, this kind of garnet resembles [[Chrysoberyl#Alexandrite|alexandrite]].<ref>{{cite journal |last1=Krambrock |first1=K. |last2=Guimarães |first2=F. S. |last3=Pinheiro |first3=M. V. B. |last4=Paniago |first4=R. |last5=Righi |first5=A. |last6=Persiano |first6=A. I. C. |last7=Karfunkel |first7=J. |last8=Hoover |first8=D. B. |title=Purplish-red almandine garnets with alexandrite-like effect: causes of colors and color-enhancing treatments |journal=Physics and Chemistry of Minerals |date=July 2013 |volume=40 |issue=7 |pages=555–562 |doi=10.1007/s00269-013-0592-6|bibcode=2013PCM....40..555K |s2cid=95448333 }}</ref>

===Ugrandite group – calcium in ''X'' site===
*[[Andradite]]: Ca<sub>3</sub>Fe<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>
*[[Grossular]]: Ca<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>
*[[Uvarovite]]: Ca<sub>3</sub>Cr<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>

====Andradite====
Andradite is a calcium-iron garnet, Ca<sub>3</sub>Fe<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>, is of variable composition and may be red, yellow, brown, green or black.<ref name="Klein-1993"/> The recognized varieties are [[demantoid]] (green), [[melanite]] (black),<ref name="Klein-1993"/> and topazolite (yellow or green). The red-brown translucent variety of [[colophonite]] is recognized as a partially obsolete name.<ref name="mindat">[https://www.mindat.org/min-10078.html Colophonite] (a variety of Andradite): information about the mineral ''colophonite'' in the Mindat database.</ref> Andradite is found in [[skarn]]s<ref name="Klein-1993"/> and in deep-seated [[igneous rock]]s like [[syenite]]<ref>{{cite journal |last1=Saha |first1=Abhishek |last2=Ray |first2=Jyotisankar |last3=Ganguly |first3=Sohini |last4=Chatterjee |first4=Nilanjan |title=Occurrence of melanite garnet in syenite and ijolite–melteigite rocks of Samchampi–Samteran alkaline complex, Mikir Hills, Northeastern India |journal=Current Science |date=10 July 2011 |volume=101 |issue=1 |pages=95–100 |jstor=24077869}}</ref> as well as serpentines<ref>{{cite journal |last1=Plümper |first1=Oliver |last2=Beinlich |first2=Andreas |last3=Bach |first3=Wolfgang |last4=Janots |first4=Emilie |last5=Austrheim |first5=Håkon |title=Garnets within geode-like serpentinite veins: Implications for element transport, hydrogen production and life-supporting environment formation |journal=Geochimica et Cosmochimica Acta |date=September 2014 |volume=141 |pages=454–471 |doi=10.1016/j.gca.2014.07.002|bibcode=2014GeCoA.141..454P }}</ref> and [[greenschist]]s.<ref>{{cite journal |last1=Coombs |first1=D. S. |last2=Kawachi |first2=Y. |last3=Houghton |first3=B. F. |last4=Hyden |first4=G. |last5=Pringle |first5=I. J. |last6=Williams |first6=J. G. |title=Andradite and andradite-grossular solid solutions in very low-grade regionally metamorphosed rocks in Southern New Zealand |journal=Contributions to Mineralogy and Petrology |date=August 1977 |volume=63 |issue=3 |pages=229–246 |doi=10.1007/BF00375574|bibcode=1977CoMP...63..229C |s2cid=129908263 }}</ref> Demantoid is one of the most prized of garnet varieties.<ref>{{cite journal |last1=Phillips |first1=Wm. Revell |last2=Talantsev |first2=Anatoly S. |title=Russian demantoid, czar of the garnet family |journal=Gems & Gemology |date=Summer 1996 |volume=32 |issue=2 |pages=100–111 |doi=10.5741/GEMS.32.2.100 |url=https://www.gia.edu/doc/Russian-Demantoid-Czar-of-the-Garnet-Family.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.gia.edu/doc/Russian-Demantoid-Czar-of-the-Garnet-Family.pdf |archive-date=2022-10-09 |url-status=live |access-date=7 December 2020}}</ref>

====Grossular====
[[File:Grossular garnet from Quebec, collected by Dr John Hunter in the 18th century, Hunterian Museum, Glasgow.jpg|thumb|Grossular garnet from Quebec, collected by Dr John Hunter in the 18th century, Hunterian Museum, Glasgow]]
[[File:GrossularShades.jpg|thumb|right|Grossular garnets on display at the U.S. [[National Museum of Natural History]]. The green gem at right is a type of grossular known as [[tsavorite]].]]

Grossular is a calcium-aluminium garnet with the formula Ca<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the [[botany|botanical]] name for the [[gooseberry]], ''grossularia'', in reference to the green garnet of this composition that is found in [[Siberia]]. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow.<ref name="Klein-1993"/> Because of its inferior hardness to [[zircon]], which the yellow crystals resemble, they have also been called ''hessonite'' from the [[Greek language|Greek]] meaning inferior.<ref>{{cite journal |last1=Modreski |first1=Peter J. |title=Featured Mineral Group at the 1993 Tucson Show: Garnet |journal=Rocks & Minerals |date=1 February 1993 |volume=68 |issue=1 |pages=20–33 |doi=10.1080/00357529.1993.9926521|bibcode=1993RoMin..68...20M }}</ref> Grossular is found in skarns,<ref name="Klein-1993"/> contact metamorphosed [[limestone]]s with [[vesuvianite]], [[diopside]], [[wollastonite]] and [[wernerite]].

Grossular garnet from [[Kenya]] and [[Tanzania]] has been called tsavorite. Tsavorite was first described in the 1960s in the [[:Category:Tsavo National Park|Tsavo]] area of Kenya, from which the gem takes its name.<ref>[http://www.mindat.org/min-7836.html Mindat.org - Tsavorite]</ref><ref>{{cite journal |last1=Feneyrol |first1=J. |last2=Giuliani |first2=G. |last3=Ohnenstetter |first3=D. |last4=Fallick |first4=A.E. |last5=Martelat |first5=J.E. |last6=Monié |first6=P. |last7=Dubessy |first7=J. |last8=Rollion-Bard |first8=C. |last9=Le Goff |first9=E. |last10=Malisa |first10=E. |last11=Rakotondrazafy |first11=A.F.M. |last12=Pardieu |first12=V. |last13=Kahn |first13=T. |last14=Ichang'i |first14=D. |last15=Venance |first15=E. |last16=Voarintsoa |first16=N.R. |last17=Ranatsenho |first17=M.M. |last18=Simonet |first18=C. |last19=Omito |first19=E. |last20=Nyamai |first20=C. |last21=Saul |first21=M. |title=New aspects and perspectives on tsavorite deposits |journal=Ore Geology Reviews |date=September 2013 |volume=53 |pages=1–25 |doi=10.1016/j.oregeorev.2013.01.016|bibcode=2013OGRv...53....1F }}</ref>

====Uvarovite====
Uvarovite is a calcium chromium garnet with the formula Ca<sub>3</sub>Cr<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>. This is a rather rare garnet, bright green in color, usually found as small crystals associated with [[chromite]] in [[peridotite]], [[serpentinite]], and kimberlites. It is found in crystalline [[marble]]s and schists in the [[Ural Mountains]] of Russia and [[Outokumpu, Finland]]. Uvarovite is named for [[Sergey Uvarov|Count Uvaro]], a Russian imperial statesman.<ref name="Klein-1993" />

===Less common species===
*Calcium in ''X'' site
**[[Goldmanite]]: {{chem2|Ca3(V^{3+},Al,Fe^{3+})2(SiO4)3}}
**Kimzeyite: {{chem2|Ca3([[Zr]], [[Ti]])2[(Si,Al,Fe^{3+})O4]3}}
**Morimotoite: {{chem2|Ca3Ti^{4+}Fe^{2+}(SiO4)3}}
**Schorlomite: {{chem2|Ca3Ti^{4+}2(SiO4)(Fe^{3+}O4)2}}
*Hydroxide bearing – calcium in ''X'' site
**[[Hydrogrossular]]: {{chem2|Ca3Al2(SiO4)_{3–x}(OH)_{4x} }}
***Hibschite: {{chem2|Ca3Al2(SiO4)_{3−x}(OH)_{4x} }} (where x is between 0.2 and 1.5)
***Katoite: {{chem2|Ca3Al2(SiO4)_{3−x}(OH)_{4x} }} (where x is greater than 1.5)
*Magnesium or manganese in ''X'' site
**[[Knorringite]]: {{chem2|Mg3Cr2(SiO4)3}}
**[[Majorite]]: {{chem2|Mg3(Fe^{2+}Si)(SiO4)3}}
**[[Calderite]]: {{chem2|Mn3Fe^{3+}2(SiO4)3}}

====Knorringite====
Knorringite is a magnesium-chromium garnet species with the formula Mg<sub>3</sub>Cr<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>. Pure [[endmember]] knorringite never occurs in nature. Pyrope rich in the knorringite component is only formed under high pressure and is often found in [[kimberlite]]s. It is used as an indicator mineral in the search for [[diamond]]s.<ref>{{cite journal |last1=Nixon |first1=Peter H. |last2=Hornung |first2=George |title=A new chromium garnet end member, knorringite, from Kimberlite |journal=American Mineralogist |date=1968 |volume=53 |issue=11–12 |pages=1833–1840 |url=https://pubs.geoscienceworld.org/msa/ammin/article-abstract/53/11-12/1833/542536 |access-date=7 December 2020}}</ref>