Editing Garnet (section)

===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>