View source for Garnet

{{short description|Mineral, semi-precious stone}}
{{Other uses}}
{{shortlead|date=January 2024}}
{{Infobox mineral
| name        = Garnet
| category    = [[Nesosilicate]]
| boxwidth    = 
| boxbgcolor  = #733635
| boxtextcolor = white
| image       = Garnet Andradite20.jpg
| alt         = 
| caption     = 
| formula     =  The general formula <!--
                -->''X''<sub>3</sub>''Y''<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub>
| IMAsymbol   = Grt<ref>{{Cite journal|last=Warr|first=L. N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref>
| molweight   = 
| symmetry = Ia3d
| class = <math>4/m\bar{3} 2/m</math>
| color       = virtually all colors, blue is rare 
| habit       = [[Rhombic dodecahedron]] or cubic
| system      = [[Cubic (crystal system)|Isometric]]
| twinning    = 
| cleavage    = Indistinct
| fracture    = conchoidal to uneven
| mohs        = 6.5–7.5
| luster      = vitreous to resinous
| diaphaneity = Can form with any diaphaneity, translucent is common
| polish      = vitreous to subadamantine<ref name="GRG"/>
| refractive  = 1.72–1.94
| opticalprop = Single refractive, often anomalous double refractive<ref name="GRG"/>
| birefringence = None
| pleochroism = None
| streak      = White
| gravity     = 3.1–4.3
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| fluorescence= variable
| other       = variable magnetic attraction
| var1 = Pyrope       | var1text = Mg<sub>3</sub>Al<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
| var2 = Almandine    | var2text = Fe<sub>3</sub>Al<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
| var3 = Spessartine  | var3text = Mn<sub>3</sub>Al<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
| var4 = Andradite    | var4text = Ca<sub>3</sub>Fe<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
| var5 = Grossular    | var5text = Ca<sub>3</sub>Al<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
| var6 = Uvarovite    | var6text = Ca<sub>3</sub>Cr<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>
}}

'''Garnets''' ({{IPAc-en|pron|ˈ|ɡ|ɑr|n|ᵻ|t}}) are a group of [[silicate mineral]]s that have been used since the [[Bronze Age]] as [[gemstone]]s and [[abrasive]]s.

All species of garnet possess similar physical properties and crystal forms but differ in [[chemical composition]]. The different species are [[pyrope]], [[almandine]], [[spessartine]], [[grossular]] (varieties of which are [[hessonite]] or cinnamon-stone and [[tsavorite]]), [[uvarovite]] and [[andradite]]. The garnets make up two [[solid solution]] series: pyrope-almandine-spessartine (pyralspite), with the composition range {{chem2|[Mg,Fe,Mn]3Al2(SiO4)3}}; and uvarovite-grossular-andradite (ugrandite), with the composition range {{chem2|Ca3[Cr,Al,Fe]2(SiO4)3}}.

==Etymology==
The word ''garnet'' comes from the 14th-century [[Middle English]] word ''gernet'', meaning 'dark red'. It is borrowed from Old French ''grenate'' from [[Latin language|Latin]] ''granatus,'' from ''granum'' ('grain, seed').<ref name="Klein-1993">{{cite book |last1=Klein |first1=Cornelis |last2=Hurlbut | first2=Cornelius S. Jr. |title=Manual of mineralogy : (after James D. Dana) |date=1993 |publisher=Wiley |location=New York |isbn=047157452X |pages=451–454 |edition=21st}}</ref> This is possibly a reference to ''mela granatum'' or even ''pomum granatum'' ('[[pomegranate]]',<ref>[http://www.etymonline.com/index.php?term=pomegranate pomegranate]. Online Etymology Dictionary. Retrieved on 2011-12-25.</ref> ''Punica granatum''), a plant whose fruits contain abundant and vivid red seed covers ([[aril]]s), which are similar in shape, size, and color to some garnet crystals.<ref>[http://www.etymonline.com/index.php?term=garnet garnet]. Online Etymology Dictionary. Retrieved on 2011-12-25.</ref> Hessonite garnet is also named 'gomed' in Indian literature and is one of the nine jewels in Vedic astrology that comprise the [[Navaratna]].<ref>{{Cite book |last=Brown |first=Richard |url=https://archive.org/details/ancientastrologi0000brow/page/47/mode/2up |title=Ancient astrological gemstones & talismans : the complete science of planetary gemology |date=1995 |publisher=A.G.T. Co |isbn=974-89022-4-2 |location=Bangkok |pages=47 |oclc=33190408}}</ref>

==Physical properties==
===Properties===
[[File:Garnet.JPG|thumb|left|A sample showing the deep red color garnet can exhibit.]]

Garnet species are found in every colour, with reddish shades most common. Blue garnets are the rarest and were first reported in the 1990s.{{sfn|Klein|Hurlbut|1993|p=600}}<ref>{{cite journal |last1=Galoisy |first1=L. |title=Garnet: From Stone to Star |journal=Elements |date=1 December 2013 |volume=9 |issue=6 |pages=453–456 |doi=10.2113/gselements.9.6.453|bibcode=2013Eleme...9..453G }}</ref><ref name="blue"/><ref>{{cite journal |last1=Baxter |first1=Ethan F. |last2=Caddick |first2=Mark J. |last3=Ague |first3=Jay J. |title=Garnet: Common Mineral, Uncommonly Useful |journal=Elements |date=1 December 2013 |volume=9 |issue=6 |pages=415–419 |doi=10.2113/gselements.9.6.415|bibcode=2013Eleme...9..415B }}</ref>

Garnet species' light transmission properties can range from the gemstone-quality transparent specimens to the opaque varieties used for industrial purposes as abrasives. The mineral's [[lustre (mineralogy)|lustre]] is categorized as [[vitreous lustre|vitreous]] (glass-like) or resinous (amber-like).<ref name="Klein-1993"/>

===Crystal structure===
Garnets are [[Silicate minerals#Nesosilicates or Isosilicates|nesosilicates]] having the general formula ''X''<sub>3</sub>''Y''<sub>2</sub>({{chem|[[silicon|Si]]|[[oxygen|O]]|4}})<sub>3</sub>. The ''X'' site is usually occupied by divalent cations ([[calcium|Ca]], [[magnesium|Mg]], [[iron|Fe]], [[manganese|Mn]])<sup>2+</sup> and the ''Y'' site by trivalent cations ([[aluminium|Al]]<sup>3+</sup>, Fe<sup>3+</sup>, [[chromium|Cr]]<sup>3+</sup>) in an [[octahedron|octahedral]]/[[tetrahedron|tetrahedral]] framework with [SiO<sub>4</sub>]<sup>4−</sup> occupying the tetrahedra.<ref>{{cite web | last = Smyth | first = Joe | title = Mineral Structure Data | work = Garnet | publisher = University of Colorado | url = http://ruby.colorado.edu/~smyth/min/garnet.html | access-date = 2007-01-12 | archive-date = 2007-01-16 | archive-url = https://web.archive.org/web/20070116233247/http://ruby.colorado.edu/~smyth/min/garnet.html | url-status = dead }}</ref>  Garnets are most often found in the [[dodecahedral]] [[crystal habit]], but are also commonly found in the [[trapezohedron]] habit as well as the [[Hexoctahedron|hexoctahedral]] habit.<ref name="Klein-1993" /> They crystallize in the [[Cubic (crystal system)|cubic]] system, having three axes that are all of equal length and perpendicular to one another but are never actually cubic because, despite being isometric, the {100} and {111} families of planes are depleted.<ref name="Klein-1993" /> Garnets do not have any [[Cleavage (crystal)|cleavage]] planes, so, when they fracture under stress, sharp, irregular ([[conchoidal]]) pieces are formed.<ref>{{cite book |last1=Nesse |first1=William D. |title=Introduction to mineralogy |date=2000 |publisher=Oxford University Press |location=New York |isbn=9780195106916 |page=311}}</ref>

<gallery>
File:Pyrope cp.jpg|Crystal structure of pyrope garnet. White spheres are oxygen; black, silicon; blue, aluminium; and red, magnesium.
File:Pyrope crystal structure.jpg|Same view, with ion sizes reduced to better show all ions
File:Pyrope si.jpg|Silicon ion size exaggerated to emphasize silica tetrahedra
</gallery>

===Hardness===
Because the chemical composition of garnet varies, the atomic bonds in some species are stronger than in others. As a result, this mineral group shows a range of hardness on the [[Mohs scale of mineral hardness|Mohs scale]] of about 6.0 to 7.5.<ref>{{Cite book|last1=Deer|first1=W. A.|url=https://pubs.geoscienceworld.org/books/book/952/An-Introduction-to-the-Rock-Forming-Minerals|title=An Introduction to the Rock-Forming Minerals|last2=Howie|first2=R. A.|last3=Zussman|first3=J.|publisher=Mineralogical Society of Great Britain and Ireland|year=2013|isbn=9780903056434|chapter=Garnet Group}}</ref> The harder species like [[almandine]] are often used for abrasive purposes.<ref>{{cite journal |last1=Perec |first1=Andrzej |title=Disintegration and recycling possibility of selected abrasives for water jet cutting |journal=DYNA |date=1 October 2017 |volume=84 |issue=203 |pages=249–256 |doi=10.15446/dyna.v84n203.62592|doi-access=free }}</ref>

===Magnetics used in garnet series identification===
For gem identification purposes, a pick-up response to a strong [[neodymium magnet]] separates garnet from all other natural transparent gemstones commonly used in the jewelry trade. [[Magnetic susceptibility]] measurements in conjunction with refractive index can be used to distinguish garnet species and varieties, and determine the composition of garnets in terms of percentages of end-member species within an individual gem.<ref>D. B. Hoover, B. Williams, C. Williams and C. Mitchell, [http://www.stonegrouplabs.com/magnetics_garnetchemistry.pdf Magnetic susceptibility, a better approach to defining garnets] {{Webarchive|url=https://web.archive.org/web/20111005095124/http://www.stonegrouplabs.com/magnetics_garnetchemistry.pdf |date=2011-10-05 }}, The Journal of Gemmology, 2008, Volume 31, No. 3/4 pp. 91–103</ref>

==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>

== Garnet structural group ==
*Formula: X<sub>3</sub>Z<sub>2</sub>(TO<sub>4</sub>)<sub>3</sub> (X = Ca, Fe, etc., Z = Al, Cr, etc., T = Si, As, V, Fe, Al) 
**All are cubic or strongly pseudocubic.

{| class="wikitable"
|-
! IMA/CNMNC <br/>Nickel-Strunz <br/>Mineral class !! Mineral name !! Formula !! Crystal system !! Point group !! Space group
|-
| 04 Oxide || [[Bitikleite-(SnAl)]]|| Ca<sub>3</sub>SnSb(AlO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| 04 Oxide || [[Bitikleite-(SnFe)]]|| Ca<sub>3</sub>(SnSb<sup>5+</sup>)(Fe<sup>3+</sup>O<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| 04 Oxide || [[Bitikleite-(ZrFe)]]|| Ca<sub>3</sub>SbZr(Fe<sup>3+</sup>O<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| 04 Tellurate || [[Yafsoanite]]|| Ca<sub>3</sub>Zn<sub>3</sub>(Te<sup>6+</sup>O<sub>6</sub>)<sub>2</sub> || isometric || m{{overline|3}}m <br/>or 432 || Ia{{overline|3}}d <br/> or I4<sub>1</sub>32
|-
| 08 Arsenate || [[Berzeliite]]|| NaCa<sub>2</sub>Mg<sub>2</sub>(AsO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| 08 Vanadate || [[Palenzonaite]]|| NaCa<sub>2</sub>Mn<sup>2+</sup><sub>2</sub>(VO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| 08 Vanadate || [[Schäferite]] || NaCa<sub>2</sub>Mg<sub>2</sub>(VO<sub>4</sub>)<sub>3</sub> ||  isometric || m{{overline|3}}m || Ia{{overline|3}}d
|}

*IMA/CNMNC – Nickel-Strunz – Mineral subclass: 09.A Nesosilicate
**[[Strunz classification|Nickel-Strunz classification]]: 09.AD.25

{| class="wikitable"
|-
! Mineral name !! Formula !! Crystal system !! Point group !! Space group
|-
| [[Almandine]] || Fe<sup>2+</sup><sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Andradite]] || Ca<sub>3</sub>Fe<sup>3+</sup><sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Calderite]] || Mn<sup>+2</sup><sub>3</sub>Fe<sup>+3</sup><sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Goldmanite]] || Ca<sub>3</sub>V<sup>3+</sup><sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Grossular]] || Ca<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-

| [[Henritermierite]]|| Ca<sub>3</sub>Mn<sup>3+</sup><sub>2</sub>(SiO<sub>4</sub>)<sub>2</sub>(OH)<sub>4</sub> || tetragonal || 4/mmm || I4<sub>1</sub>/acd
|-
| [[Hibschite]]|| Ca<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>(3−x)</sub>(OH)<sub>4x</sub> (x= 0.2–1.5) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Katoite]]|| Ca<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>(3−x)</sub>(OH)<sub>4x</sub> (x= 1.5–3) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Kerimasite]]|| Ca<sub>3</sub>Zr<sub>2</sub>(Fe<sup>+3</sup>O<sub>4</sub>)<sub>2</sub>(SiO<sub>4</sub>) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Kimzeyite]]|| Ca<sub>3</sub>Zr<sub>2</sub>(Al<sup>+3</sup>O<sub>4</sub>)<sub>2</sub>(SiO<sub>4</sub>) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Knorringite]] || Mg<sub>3</sub>Cr<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Majorite]] || Mg<sub>3</sub>(Fe<sup>2+</sup>Si)(SiO<sub>4</sub>)<sub>3</sub> || tetragonal || 4/m <br/>or 4/mmm || I4<sub>1</sub>/a <br/>or I4<sub>1</sub>/acd
|-
|[[Menzerite-(Y)]]|| Y<sub>2</sub>CaMg<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Momoiite]]|| Mn<sup>2+</sup><sub>3</sub>V<sup>3+</sup><sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Morimotoite]]|| Ca<sub>3</sub>(Fe<sup>2+</sup>Ti<sup>4+</sup>)(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Pyrope]] || Mg<sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Schorlomite]] || Ca<sub>3</sub>Ti<sup>4+</sup><sub>2</sub>(Fe<sup>3+</sup>O<sub>4</sub>)<sub>2</sub>(SiO<sub>4</sub>) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Spessartine]] || Mn<sup>2+</sup><sub>3</sub>Al<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Toturite]]|| Ca<sub>3</sub>Sn<sub>2</sub>(Fe<sup>3+</sup>O<sub>4</sub>)<sub>2</sub>(SiO<sub>4</sub>) || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|-
| [[Uvarovite]] || Ca<sub>3</sub>Cr<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> || isometric || m{{overline|3}}m || Ia{{overline|3}}d
|}
*References: [[Mindat.org]]; mineral name, chemical formula and space group (American Mineralogist Crystal Structure Database) of the IMA Database of Mineral Properties/ RRUFF Project, Univ. of Arizona, was preferred most of the time. Minor components in formulae have been left out to highlight the dominant chemical endmember that defines each species.

==Synthetic garnets==
Also known as rare-earth garnets.

The crystallographic structure of garnets has been expanded from the prototype to include chemicals with the general formula ''A''<sub>3</sub>''B''<sub>2</sub>(''C''O<sub>4</sub>)<sub>3</sub>.  Besides silicon, a large number of elements have been put on the ''C'' site, including [[germanium]], [[gallium]], [[aluminum]], [[vanadium]] and [[iron]].<ref>S. Geller ''Crystal chemistry of the garnets'' Zeitschrift für Kristallographie, '''125'''(125), pp. 1–47 (1967) {{doi|10.1524/zkri.1967.125.125.1}}</ref>

[[Yttrium aluminium garnet]] (YAG), Y<sub>3</sub>Al<sub>2</sub>(AlO<sub>4</sub>)<sub>3</sub>, is used for [[Chemical synthesis|synthetic]] gemstones. Due to its fairly high refractive index, YAG was used as a diamond simulant in the 1970s until the methods of producing the more advanced simulant [[cubic zirconia]] in commercial quantities were developed. When doped with [[neodymium]] (Nd<sup>3+</sup>), [[erbium]] or [[gadolinium]] YAG may be used as the [[lasing medium]] in [[Nd:YAG laser]]s,<ref>{{Cite book|last=Yariv|first=Amnon|title=Quantum Electronics|publisher=Wiley|year=1989|isbn=978-0-471-60997-1|edition=3rd|pages=208–211}}</ref> [[Er:YAG laser]]s and [[Gadolinium yttrium garnet|Gd:YAG lasers]] respectively. These doped YAG lasers are used in medical procedures including [[laser skin resurfacing]], dentistry, and ophthalmology.<ref>{{Cite journal|last1=Teikemeier|first1=G|last2=Goldberg|first2=DJ|date=1997|title=Skin resurfacing with the erbium:YAG laser|journal=Dermatologic Surgery|location=Philadelphia|publisher=Lippincott Williams & Wilkins|volume=23|issue=8|pages=685–687|doi=10.1111/j.1524-4725.1997.tb00389.x|pmid=9256915|s2cid=31557815}}</ref><ref>{{Cite journal|last=Bornstein|first=E|date=2004|title=Proper use of Er:YAG lasers and contact sapphire tips when cutting teeth and bone: scientific principles and clinical application|journal=Dentistry Today|volume=23|issue=83|pages=86–89|pmid=15354712}}</ref><ref>{{Cite journal|last1=Kokavec|first1=Jan|last2=Wu|first2=Zhichao|last3=Sherwin|first3=Justin C|last4=Ang|first4=Alan JS|last5=Ang|first5=Ghee Soon|date=2017-06-01|title=Nd:YAG laser vitreolysis versus pars plana vitrectomy for vitreous floaters|journal=The Cochrane Database of Systematic Reviews|volume=2017|issue=6|pages=CD011676|doi=10.1002/14651858.CD011676.pub2|issn=1469-493X|pmc=6481890|pmid=28570745}}</ref>

Interesting magnetic properties arise when the appropriate elements are used. In [[yttrium iron garnet]] (YIG), Y<sub>3</sub>Fe<sub>2</sub>(FeO<sub>4</sub>)<sub>3</sub>, the five iron(III) ions occupy two [[octahedral]] and three [[tetrahedral]] sites, with the yttrium(III) ions coordinated by eight oxygen ions in an irregular cube. The iron ions in the two coordination sites exhibit different [[Spin (physics)|spins]], resulting in [[magnetic]] behavior. YIG is a [[Ferrimagnetism|ferrimagnetic]] material having a [[Curie point|Curie temperature]] of 550&nbsp;[[Kelvin|K]]. Yttrium iron garnet can be made into [[YIG sphere]]s, which serve as magnetically tunable [[Signal processing|filters]] and [[resonators]] for [[microwave]] frequencies.<ref>{{Cite web |title=What is YIG and How Does It Work So Well? |url=https://www.microlambdawireless.com/updates/what-is-yig-and-why-does-it-work-so-well/ |access-date=2023-07-17 |website=www.microlambdawireless.com}}</ref>

[[Lutetium aluminium garnet]] (LuAG), {{chem2|Al5[[Lutetium|Lu3]]O12}}, is an inorganic compound with a unique crystal structure primarily known for its use in high-efficiency laser devices. LuAG is also useful in the synthesis of [[transparent ceramics]].<ref>{{Cite journal|last=Moore|first=Cheryl|date=2015|title=Towards a Greater Understanding of Hydrothermally Grown Garnets and Sesquioxide Crystals for Laser Applications|journal=Clemson University Tiger Prints|bibcode=2015PhDT.......308M}}</ref> LuAG is particularly favored over other crystals for its high density and thermal conductivity; it has a relatively small [[lattice constant]] in comparison to the other [[Rare-earth element|rare-earth]] garnets, which results in a higher density producing a crystal field with narrower linewidths and greater energy level splitting in absorption and emission.<ref>{{Cite web|title=Lutetium Aluminum Garnet - LuAG - Lu3Al5O12|url=http://scientificmaterials.com/products/luag_Lu3Al5O12_lutetium_aluminum.php|access-date=2016-04-29|website=scientificmaterials.com}}</ref>

[[Terbium gallium garnet|Terbium gallium garnet (TGG)]], {{chem2|[[Terbium|Tb3]]Ga5O12}}, is a [[Faraday rotator]] material with excellent transparency properties and is very resistant to laser damage. TGG can be used in [[optical isolator]]s for laser systems, in [[optical circulator]]s for fiber optic systems, in [[optical modulator]]s, and in current and [[magnetometer|magnetic field]] sensors.<ref>{{Cite journal|last1=Majeed|first1=Hassaan|last2=Shaheen|first2=Amrozia|last3=Anwar|first3=Muhammad Sabieh|date=2013|title=Complete Stokes polarimetry of magneto-optical Faraday effect in a terbium gallium garnet crystal at cryogenic temperatures|url=https://www.osapublishing.org/captcha/(S(rogajdpzcsrcfvq3qgqu45d0))/?guid=70569AD2-E129-C404-B892-854EC43AA69E|journal=Optics Express|location=Washington, D.C.|publisher=The Optical Society|volume=21|issue=21|pages=25148–25158|doi=10.1364/OE.21.025148|pmid=24150356|bibcode=2013OExpr..2125148M|doi-access=free}}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Another example is [[gadolinium gallium garnet|gadolinium gallium garnet (GGG)]], {{chem2|[[Gadolinium|Gd3]]Ga2(GaO4)3}} which is synthesized for use as a substrate for liquid-phase epitaxy of magnetic garnet films for [[bubble memory]] and [[Photomagnetism|magneto-optical]] applications.{{Citation needed|date=February 2021}}

== Geological importance ==
[[File:Grenat.jpg|thumb|upright=1.5|Main garnet producing countries]]
[[File:Garnet var. Spessartine, Putian City, Putian Prefecture, Fujian Province, China.jpg|thumb|Garnet var. Spessartine, Putian City, Putian Prefecture, Fujian Province, China]]
The mineral garnet is commonly found in metamorphic and to a lesser extent, igneous rocks. Most natural garnets are compositionally zoned and contain inclusions.<ref>{{Cite book|last=Nesse|first=William D.|title=Introduction to Optical Mineralogy|publisher=Oxford University Press|year=2013|isbn=978-0-19-984628-3|edition=International Fourth|location=New York|pages=252–255}}</ref> Its crystal lattice structure is stable at high pressures and temperatures and is thus found in green-schist facies metamorphic rocks including [[gneiss]], hornblende [[schist]], and mica schist.<ref name="Klein-1985">{{Cite book|last1=Klein|first1=C|title=Manual of Mineralogy|last2=Hurlbut|first2=C. D.|publisher=John Wiley and Sons|year=1985|isbn=0-471-80580-7|location=New York|pages=375–378}}</ref> The composition that is stable at the pressure and temperature conditions of Earth's mantle is pyrope, which is often found in [[peridotites]] and [[kimberlite]]s, as well as the [[Serpentine subgroup|serpentines]] that form from them.<ref name="Klein-1985" /> Garnets are unique in that they can record the pressures and temperatures of peak metamorphism and are used as geobarometers and geothermometers in the study of [[geothermobarometry]] which determines "P-T Paths", Pressure-Temperature Paths. Garnets are used as an index mineral in the delineation of [[isograd]]s in metamorphic rocks.<ref name="Klein-1985" /> Compositional zoning and inclusions can mark the change from growth of the crystals at low temperatures to higher temperatures.<ref name="Teaching Phase Equilibria">{{Cite web|title=P-T-t Paths|url=https://serc.carleton.edu/research_education/equilibria/PTtPaths.html|website=Teaching Phase Equilibria|language=en|access-date=2020-03-19}}</ref> Garnets that are not compositionally zoned more than likely experienced ultra high temperatures (above 700&nbsp;°C) that led to diffusion of major elements within the crystal lattice, effectively homogenizing the crystal<ref name="Teaching Phase Equilibria" /> or they were never zoned. Garnets can also form metamorphic textures that can help interpret structural histories.<ref name="Teaching Phase Equilibria" />

In addition to being used to devolve conditions of metamorphism, garnets can be used to date certain geologic events. Garnet has been developed as a U-Pb [[Geochronometry|geochronometer]], to date the age of crystallization<ref>{{Cite journal|last1=Seman|first1=S.|last2=Stockli|first2=D. F.|last3=McLean|first3=N. M.|date=2017-06-05|title=U-Pb geochronology of grossular-andradite garnet|url=http://www.sciencedirect.com/science/article/pii/S0009254117302541|journal=Chemical Geology|language=en|volume=460|pages=106–116|doi=10.1016/j.chemgeo.2017.04.020|bibcode=2017ChGeo.460..106S|issn=0009-2541}}</ref> as well as a [[Thermochronology|thermochronometer]] in the (U-Th)/He system<ref>{{Cite journal|last1=Blackburn|first1=Terrence J.|last2=Stockli|first2=Daniel F.|last3=Carlson|first3=Richard W.|last4=Berendsen|first4=Pieter|date=2008-10-30|title=(U–Th)/He dating of kimberlites—A case study from north-eastern Kansas|url=http://www.sciencedirect.com/science/article/pii/S0012821X08005323|journal=Earth and Planetary Science Letters|language=en|volume=275|issue=1|pages=111–120|doi=10.1016/j.epsl.2008.08.006|bibcode=2008E&PSL.275..111B|issn=0012-821X}}</ref> to date timing of cooling below a [[closure temperature]].

Garnets can be chemically altered and most often alter to serpentine, [[talc]], and [[Chlorite group|chlorite]].<ref name="Klein-1985" />

===Largest garnet crystal===
The open-pit Barton Garnet Mine, located at [[Gore Mountain (New York)|Gore Mountain]] in the [[Adirondack Mountains]], yields the world's largest single crystals of garnet; diameters range from 5 to 35&nbsp;cm and commonly average 10–18&nbsp;cm.<ref name="Geophere">{{cite journal | title= Megacrystic Gore Mountain–type garnets in the Adirondack Highlands: Age, origin, and tectonic implications | year= 2011 | publisher=Geological Society of America| doi= 10.1130/GES00683.1 | last1= McLelland | first1= James M. | last2= Selleck | first2= Bruce W. | journal= Geosphere | volume= 7 | issue= 5 | pages= 1194–1208 | bibcode= 2011Geosp...7.1194M | doi-access= free }}</ref>

[[Gore Mountain Garnet|Gore Mountain garnet]]s are unique in many respects, and considerable effort has been made to determine the timing of garnet growth. The first dating was that of Basu et al. (1989), who used plagioclase-hornblende-garnet to produce a Sm/Nd isochron that yielded an age of 1059 ± 19 Ma. Mezger et al. (1992) conducted their own Sm/Nd investigation using hornblende and the drilled core of a 50&nbsp;cm garnet to produce an isochron age of 1051 ± 4 Ma. Connelly (2006) utilized seven different fractions of a Gore Mountain garnet to obtain a Lu-Hf isochron age of 1046.6 ± 6 Ma. It is therefore concluded with confidence that the garnets formed at 1049 ± 5 Ma, the average of the three determinations. This is also the local age of peak metamorphism in the 1090–1040 Ma Ottawan phase of the [[Grenville orogeny|Grenvillian orogeny]] and serves as a critical data point in ascertaining the evolution of the megacrystic garnet deposits.<ref name="Geophere"/>

==Uses==
[[File:Flickr - portableantiquities - Hilt Fitting.jpg|thumb|c. 7th century AD, [[Anglo-Saxon art|Anglo-Saxon]] [[seax]] hilt fitting – gold with gemstone inlay of [[garnet cloisonné]].  From the [[Staffordshire Hoard]], found in 2009, and not fully cleaned]]
[[File:garnet.uvarovite.500pix.jpg|thumb|upright|Pendant in [[uvarovite]], a rare bright-green garnet]]

===Gemstones===
Red garnets were the most commonly used gemstones in the [[Late Antique]] [[Ancient Rome|Roman]] world, and the [[Migration Period art]] of the "[[barbarian]]" peoples who took over the territory of the [[Western Roman Empire]].  They were especially used inlaid in gold cells in the [[cloisonné]] technique, a style often just called garnet cloisonné, found from [[Anglo-Saxon]] England, as at [[Sutton Hoo]], to the [[Black Sea]]. Thousands of Tamraparniyan gold, silver and red garnet shipments were made in the [[old world]], including to Rome, Greece, the Middle East, [[Serica]] and Anglo Saxons; recent findings such as the [[Staffordshire Hoard]] and the pendant of the [[Winfarthing]] Woman skeleton of [[Norfolk]] confirm an established gem trade route with [[South India]] and [[Tamraparni]] (ancient [[Sri Lanka]]), known from antiquity for its production of gemstones.<ref>{{cite web |title=Staffordshire Hoard Festival 2019 |url=http://www.stokemuseums.org.uk/pmag/staffordshire-hoard-festival/ |website=The Potteries Museum & Art Gallery |access-date=18 June 2019 |archive-date=18 June 2019 |archive-url=https://web.archive.org/web/20190618004857/http://www.stokemuseums.org.uk/pmag/staffordshire-hoard-festival/ |url-status=dead }}</ref><ref>{{cite web |title=A trail of garnet and gold: Sri Lanka to Anglo-Saxon England |url=https://www.history.org.uk/publications/resource/9204/a-trail-of-garnet-and-gold-sri-lanka-to-anglo-sax |website=The Historical Association |access-date=18 June 2019 |language=en |date=22 June 2017}}</ref><ref>{{cite web |title=Acquisitions of the month: June 2018 |url=https://www.apollo-magazine.com/acquisitions-of-the-month-june-2018/ |website=Apollo Magazine |access-date=18 June 2019 |date=5 July 2018}}</ref>

Pure crystals of garnet are still used as gemstones. The gemstone varieties occur in shades of green, red, yellow, and orange.<ref>[http://www.geo.utexas.edu/courses/347k/redesign/gem_notes/garnet/garnet_main.htm Geological Sciences at University of Texas, Austin]. Geo.utexas.edu. Retrieved on 2011-12-25.</ref> In the United States it is known as the [[birthstone]] for January.<ref name="GRG">[[Gemological Institute of America]], ''GIA Gem Reference Guide'' 1995, {{ISBN|0-87311-019-6}}</ref><ref>{{cite web |url=http://www.jewellers-online.org/pages/tips.php?id=2&idnew=2 |archive-url=https://web.archive.org/web/20070528103836/http://www.jewellers-online.org/pages/tips.php?id=2&idnew=2 |url-status=dead |archive-date=2007-05-28 |title=Tips & Tools: Birthstones |publisher=The National Association of Goldsmiths |access-date=2014-06-16 }}</ref><ref>Kunz, George F. (1913). The curious lore of precious stones. Lippincott. pp. 275–306, pp. 319-320</ref>  It is also the birthstone of [[Aquarius (astrology)|Aquarius]] and [[Capricorn (astrology)|Capricorn]] in [[tropical astrology]].<ref>Knuth, Bruce G. (2007). Gems in Myth, Legend and Lore (Revised edition). Parachute: Jewelers Press. p. 294.</ref><ref>Kunz (1913), pp. 345–347</ref> The garnet family is one of the most complex in the gem world. It is not a single species, but is composed of multiple species and varieties.<ref>{{Cite web|title=Garnet Value, Price, and Jewelry Information|url=https://www.gemsociety.org/article/garnet-jewelry-and-gemstone-information/|access-date=2021-11-16|website=International Gem Society|language=en}}</ref> 

[[Almandine]] garnet is the state mineral of [[Connecticut]],<ref>{{cite web |url=http://www.ct.gov/ctportal/cwp/view.asp?a=885&q=246586 |title=State of Connecticut – Sites, Seals and Symbols |access-date=2009-11-12 |publisher=State of Connecticut}}</ref><ref>[http://www.sots.ct.gov/sots/cwp/view.asp?A=3188&QUESTION_ID=392608 State of Connecticut, Sites º Seals º Symbols] {{Webarchive|url=https://web.archive.org/web/20080731053844/http://www.sots.ct.gov/sots/cwp/view.asp?A=3188&QUESTION_ID=392608 |date=2008-07-31 }}; ''Connecticut State Register & Manual''; retrieved on December 20, 2008</ref> star garnet is the state gemstone of [[Idaho]],<ref>{{cite web|url=http://gov.idaho.gov/fyi/symbols/symbols_index.html |title=Idaho Symbols |access-date=2009-11-12 |publisher=State of Idaho |url-status=dead |archive-url=https://web.archive.org/web/20100630201842/http://gov.idaho.gov/fyi/symbols/symbols_index.html |archive-date=2010-06-30 }}</ref> garnet is the state gemstone of [[New York (state)|New York]],<ref name="Minerals of New York State">{{cite web |url=http://www.nysl.nysed.gov/reference/emblems.htm |title=Minerals of New York State | access-date=2022-02-25 |publisher=State of New York}}</ref><ref>[http://www.statesymbolsusa.org/New_York/gem_garnet.html New York State Gem] {{webarchive|url=https://web.archive.org/web/20071208172833/http://www.statesymbolsusa.org/New_York/gem_garnet.html |date=2007-12-08 }}; ''State Symbols USA''; retrieved on October 12, 2007</ref> and [[grossular]] garnet is the state gemstone of [[Vermont]].<ref>{{cite web |url=http://libraries.vermont.gov/general/emblems |title=Vermont Emblems |access-date=2009-11-12 |publisher=State of Vermont |url-status=dead |archive-url=https://web.archive.org/web/20091029073002/http://libraries.vermont.gov/general/emblems |archive-date=2009-10-29 }}</ref>

===Industrial uses===
Garnet sand is a good [[abrasive]], and a common replacement for silica sand in sand blasting.  Alluvial garnet grains which are rounder are more suitable for such blasting treatments. Mixed with very high pressure water, garnet is used to cut [[steel]] and other materials in [[Water jet cutter|water jets]]. For water jet cutting, garnet extracted from hard rock is suitable since it is more angular in form, therefore more efficient in cutting.<ref>{{cite web |last1=Rapple |first1=R. Randolph |title=Selecting the right waterjet abrasive |url=https://www.thefabricator.com/thefabricator/article/waterjetcutting/selecting-the-right-waterjet-abrasive |website=The Fabricator |access-date=17 July 2023}}</ref>

Garnet paper is favored by cabinetmakers for finishing bare wood.<ref>{{cite book |last=Joyce |first=Ernest |editor-first=Alan |editor-last=Peters |editor-link=Alan Peters |title=The Technique of Furniture Making |edition=4th |year=1987 |orig-year=1970 |publisher=Batsford |location=London |isbn=071344407X }}</ref>

Garnet sand is also used for [[water filtration]] media.

As an abrasive, garnet can be broadly divided into two categories; blasting grade and water jet grade. The garnet, as it is mined and collected, is crushed to finer grains; all pieces which are larger than 60&nbsp;mesh (250&nbsp;micrometers) are normally used for sand blasting. The pieces between 60&nbsp;mesh (250&nbsp;micrometers) and 200&nbsp;mesh (74&nbsp;micrometers) are normally used for water jet cutting. The remaining garnet pieces that are finer than 200&nbsp;mesh (74&nbsp;micrometers) are used for glass polishing and lapping. Regardless of the application, the larger grain sizes are used for faster work and the smaller ones are used for finer finishes.<ref>{{Cite news |last=AlphaVariable |title=Garnet |url=https://alphavariable.com/blogs/news/garnet |access-date=2024-08-08 |work=AlphaVariable |language=en}}</ref>

There are different kinds of abrasive garnets which can be divided based on their origin. The largest source of abrasive garnet today is garnet-rich beach sand which is quite abundant on [[India]]n and [[Australia]]n coasts and the main producers today are Australia and India.<ref>{{cite book|last=Briggs |first=J. |title=The Abrasives Industry in Europe and North America|year=2007 |publisher=Materials Technology Publications |isbn=978-1-871677-52-2}}</ref>

This material is particularly popular due to its consistent supplies, huge quantities and clean material. The common problems with this material are the presence of ilmenite and chloride compounds. Since the material has been naturally crushed and ground on the beaches for past centuries, the material is normally available in fine sizes only. Most of the garnet at the [[Thoothukudi|Tuticorin]] beach in south India is 80&nbsp;mesh, and ranges from 56&nbsp;mesh to 100&nbsp;mesh size.{{Citation needed|date=November 2008}}

''River garnet'' is particularly abundant in Australia. The river sand garnet occurs as a [[placer deposit]].<ref>{{Cite web |url=http://www.resourcesandenergy.nsw.gov.au/__data/assets/pdf_file/0011/237845/Garnet.pdf |title=Industrial Mineral Opportunities in New South Wales |access-date=2014-11-06 |archive-date=2014-06-22 |archive-url=https://web.archive.org/web/20140622152933/http://www.resourcesandenergy.nsw.gov.au/__data/assets/pdf_file/0011/237845/Garnet.pdf |url-status=dead }}</ref>

''Rock garnet'' is perhaps the garnet type used for the longest period of time. This type of garnet is produced in America, China and western India. These crystals are crushed in mills and then purified by wind blowing, magnetic separation, sieving and, if required, washing. Being freshly crushed, this garnet has the sharpest edges and therefore performs far better than other kinds of garnet. Both the river and the beach garnet suffer from the tumbling effect of hundreds of thousands of years which rounds off the edges. [[Gore Mountain Garnet]] from [[Warren County, New York]], USA, is a significant source of rock garnet for use as an industrial abrasive.<ref name="Klein-1993" />

==See also==
{{Portal|Minerals}}
* [[Abrasive blasting]]
{{-}}

==References==
{{reflist}}

==Further reading==
* Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed., Wiley, {{ISBN|0-471-80580-7}}
* ''Color Encyclopedia of Gemstones'', {{ISBN|0-442-20333-0}}

==External links==
{{Commons and category|Garnet|Garnet}}
*http://www.gemstonemagnetism.com contains a comprehensive section about garnets and garnet magnetism.
*[http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/garnet.html USGS Garnet locations – USA]
*http://gemstone.org/education/gem-by-gem/154-garnet
*http://www.mindat.org/min-10272.html
* [http://blogs.loc.gov/law/2012/01/garnets/ Blog post on garnets] on the [[Law Library of Congress]]'s blog
*https://www.birthstone.guide/garnet-birthstone-meaning Garnet birthstone stories

{{Gemstone}}
{{Jewelry}}

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[[Category:Magnesium minerals]]
[[Category:Symbols of Connecticut]]
[[Category:Symbols of Vermont]]
[[Category:Cubic minerals]]
[[Category:Minerals in space group 230]]
[[Category:Garnet group|*]]
[[Category:Garnet gemstones|*]]
[[Category:Industrial minerals]]
[[Category:Symbols of Tocantins]]
[[Category:Symbols of New York (state)]]