View source for Chemistry:Sugilite

{{Short description|Violet-colored crystal}}
{{Infobox mineral
| name     = Sugilite
| category = Cyclosilicate
| image    = Smithsonian Exhibit Stone.jpg 
| imagesize   = 260px
| caption  = 16kg Manganoan Sugilite, GIA Laboratory Certified, Smithsonian Exhibition Stone, I.Kurgan Royal Azel, Hall of Gems Smithsonian Museum 1981, Wessels Mine in Northern Cape Province, {{wipe|South Africa}}
| formula  = KNa<sub>2</sub>(Fe,Mn,Al)<sub>2</sub>Li<sub>3</sub>Si<sub>12</sub>O<sub>30</sub>
| IMAsymbol   = Sug<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>
| strunz   = 9.CM.05
| dana     = 63.02.01a.09
| system   = [[Physics:Hexagonal crystal system|Hexagonal]]
| class    = Dihexagonal dipyramidal (6/mmm) <br/>[[Chemistry:H-M symbol|H-M symbol]]: (6/m 2/m 2/m)
| symmetry = ''P''6/mcc
| unit cell = a = 10, c = 14&nbsp;[Å]; Z&nbsp;=&nbsp;2
| color    = Light brownish-yellow, purple, violet, reddish violet, pale pink, colorless
| habit    = Prismatic crystals, typically granular to massive
| twinning = 
| cleavage = Poor on {0001}
| fracture = 
| tenacity = 
| mohs = 6–{{frac|6|1|2}}
| luster = [[Earth:Lustre (mineralogy)#Vitreous lustre|Vitreous]]
| refractive = n<sub>ω</sub> = 1.610 n<sub>ε</sub> = 1.607
| opticalprop = Uniaxial (−)
| birefringence = δ = 0.003
| pleochroism = Weak
| streak = White
| gravity = 2.74
| density = 
| melt = 
| fusibility = 
| diagnostic = 
| solubility = 
| diaphaneity = Transparent to translucent
| other = 
| references = <ref name=Webmin>{{Cite web|last1=Barthelmy|first1=David|year=2014|url=http://www.webmineral.com/data/Sugilite.shtml|access-date=22 July 2022|title = Sugilite Mineral Data|website=Webmineral.com}}</ref><ref name=Mindat>{{mindat|id=3822|title=Sugilite}}</ref><ref name=HBM>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Sugilite |url=http://www.handbookofmineralogy.org/pdfs/sugilite.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=14 March 2022 |date=2005}}</ref>
}}

'''Sugilite''' ({{IPAc-en|ˈ|s|uː|ɡ|ə|l|aɪ|t|,_|-|dʒ|i|-}} {{respell|SOO|gə|lyte|,_|-|jee|-}})<ref name=Webmin/><ref name=Mindat/> is a relatively rare pink to purple [[Chemistry:Silicate minerals|cyclosilicate]] mineral with the complex chemical formula [[Chemistry:Potassium|K]][[Chemistry:Sodium|Na]]<sub>2</sub>([[Chemistry:Iron|Fe]], [[Chemistry:Manganese|Mn]], [[Chemistry:Aluminium|Al]])<sub>2</sub>[[Chemistry:Lithium|Li]]<sub>3</sub>[[Chemistry:Silicon|Si]]<sub>12</sub>[[Chemistry:Oxygen|O]]<sub>30</sub>. Sugilite crystallizes in the hexagonal system with prismatic crystals. The crystals are rarely found and the form is usually massive. It has a [[Chemistry:Mohs hardness|Mohs hardness]] of 5.5–6.5 and a [[Physics:Specific gravity|specific gravity]] of 2.75–2.80. It is mostly translucent.
Sugilite was first described in 1944 by the Japanese petrologist Ken-ichi Sugi (1901&ndash;1948) for an occurrence on Iwagi Islet, {{wipe|Japan}}, where it is found in an [[Chemistry:Aegirine|aegirine]] [[Chemistry:Syenite|syenite]] [[Earth:Intrusive rock|intrusive]] stock. It is found in a similar environment at [[Earth:Mont Saint-Hilaire|Mont Saint-Hilaire]], Quebec, {{wipe|Canada}}. In the Wessels mine in Northern Cape Province of {{wipe|South Africa}}, sugilite is mined from a [[Earth:Stratum|strata-bound]] [[Chemistry:Manganese|manganese]] deposit. It is also reported from Liguria and Tuscany, Italy; New South Wales, {{wipe|Australia}} and Madhya Pradesh, {{wipe|India}}.<ref name=HBM/>

Sugilite is commonly pronounced with a soft "g", as in "ginger". However, as with most minerals, its pronunciation is intended to be the same as the person it is named after; in this case, the Japanese name Sugi has a hard "g", as in "geese".<ref>{{cite web|title=OpenLearn Live: 8th September 2015 - Meet The Minerals|url=http://www.open.edu/openlearn/whats-on/events/openlearn-live-8th-september-2015#sugilite|website=OpenLearn|publisher=The Open University|access-date=20 January 2016}}</ref>

The mineral is also referred to as lavulite, luvulite, and royal azel by gem and mineral collectors.<ref name=Mindat/>

In Japan, sugilite is found as yellowish-white to colourless, and is not good for jewelery.<ref>{{cite web | url=https://gem-a.com/understanding-sugilite-gemstones-minerals | title=Understanding Sugilite &#124; Gem-A | date=15 May 2019 }}</ref>

[[File:Sugilite-162617.jpg|thumb|left|upright=1.25| Sugilite on Matrix, Wessels Mine in Northern Cape Province, South Africa, size: 2.4 x 2.1 x 1.2 cm]]
[[File:Owl in sugilite 9 cm high arp.jpg|thumb|left|Sugilite owl and mouse, height 9 cm (3.5 in)]]
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==See also==
* [[Earth:List of minerals|List of minerals]]
* [[Earth:List of minerals named after people|List of minerals named after people]]

==References==
{{Reflist}}


{{Manganese minerals}}

[[Category:Potassium minerals]]
[[Category:Sodium minerals]]
[[Category:Iron minerals]]
[[Category:Manganese minerals]]
[[Category:Aluminium minerals]]
[[Category:Lithium minerals]]
[[Category:Cyclosilicates]]
[[Category:Gemstones]]
[[Category:Hexagonal minerals]]

{{Sourceattribution|Sugilite}}