View source for Amblygonite

{{Short description|Phosphate mineral}}
{{Infobox mineral
| name        = Amblygonite
| category    = [[Phosphate minerals]]
| boxwidth    = 
| boxbgcolor  =#d1d1cf 
| image       = Mineral Ambligonita GDFL032.jpg
| imagesize   = 260px
| caption     = 
| formula     = {{chem2|(Li,Na)AlPO4(F,OH)}}
|IMAsymbol=Aby<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   = 
| strunz      = 8.BB.05
| system      = [[Triclinic]]
| class       = Pinacoidal ({{overline|1}}) <br/><small>(same [[H-M symbol]])</small>
| symmetry    = ''C''{{overline|1}}
| color       = Generally white or creamy, but can also be colorless or pale yellow, green, blue, beige, gray, brown or pink.
| habit       = Prismatic to columnar form
| twinning    = Microscopic polysynthetic twinning common
| cleavage    = [100] Perfect, [110] good, [011] distinct
| fracture    = Irregular/ineven, sub-Conchoidal
| mohs        = 5.5–6<ref name="GRG"/>
| luster      = Vitreous to pearly<ref name="GRG"/>
| polish      = greasy to vitreous (in gem material)<ref name="GRG"/>
| refractive  = n<SUB>a</SUB>=1.577 – 1.591,<br/>n<SUB>b</SUB>=1.592 – 1.605,<br/>n<SUB>c</SUB>=1.596 – 1.613
| opticalprop = Double refractive, biaxial, may be either positive or negative<ref name="GRG"/>
| birefringence = .020 – .027<ref name="GRG"/>
| dispersion  = 
| pleochroism = weak to none<ref name="GRG"/>
| fluorescence= very weak green in long wave, light blue phosphorescence in long wave and short wave<ref name="GRG">(Gia), Gemological. Gem Reference Guide. City: [[Gemological Institute of America]] (GIA), 1988. {{ISBN|0-87311-019-6}}</ref>
| absorption  =
| streak      = 
| gravity     = 2.98–3.11
| density     = 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = 
| other       = 
}}

'''Amblygonite''' ({{IPAc-en|æ|m|ˈ|b|l|ɪ|ɡ|ə|ˌ|n|aɪ|t}}) is a fluorophosphate mineral, {{chem2|(Li,Na)AlPO4(F,OH)}}, composed of [[lithium]], [[sodium]], [[aluminium]], [[phosphate]], [[fluoride]] and [[hydroxide]]. The mineral occurs in [[pegmatite]] deposits and is easily mistaken for [[albite]] and other [[feldspar]]s. Its density, cleavage and flame test for lithium are diagnostic. Amblygonite forms a series with [[montebrasite]], the low fluorine endmember. Geologic occurrence is in [[granite]] pegmatites, high-temperature [[tin]] veins, and [[greisen]]s. Amblygonite occurs with [[spodumene]], [[apatite]], [[lepidolite]], [[tourmaline]], and other lithium-bearing minerals in pegmatite veins. It contains about 10% lithium, and has been utilized as a source of lithium. The chief commercial sources have historically been the deposits of California and France.

==History==
The mineral was first discovered in [[Saxony]] by [[August Breithaupt]] in 1817, and named by him from the Greek ''amblus'', blunt, and ''gonia'', angle, because of the obtuse angle between the cleavages. Later it was found at Montebras, Creuse, [[France]], and at Hebron in [[Maine]]; and because of slight differences in optical character and chemical composition the names montebrasite and hebronite have been applied to the mineral from these localities.The term amblygonite has been used interchangeably in mining, whether this mineral or montebrasite was extracted. In fact, montebrasite is much more common than amblygonite, which is a rare mineral.<ref>{{Cite web |title=Ambligonite |url=https://www.mindat.org/min-2763.html |website=Mindat}}</ref> It has been discovered in considerable quantity at Pala in San Diego county, [[California]];  Caceres, [[Spain]]; and the [[Black Hills]] of [[South Dakota]]. A blue form of amblygonite-montebrasite has been described from Rwanda. The largest documented single crystal of amblygonite measured 7.62 × 2.44 × 1.83&nbsp;m and weighed about 102 tons.<ref>{{cite journal| url = http://www.minsocam.org/ammin/AM66/AM66_885.pdf| journal = American Mineralogist| volume = 66| pages = 885–907| year= 1981| title= The largest crystals| author = P. C. Rickwood}}</ref>

==Gemology==
Transparent amblygonite has been faceted and used as a gemstone. As a gemstone set into jewelry it is vulnerable to breakage and abrasion from general wear, as its hardness and toughness are poor.<ref name="GRG"/> The main sources for gem material are Brazil and the United States. Australia, France, Germany, Namibia, and Norway, and Spain have also produced gem quality amblygonite.<ref name="GRG"/>

[[File:Amblygonite - Taquaral, Itinga, Minas Gerais, Brazil.jpg|thumb|left|Amblygonite from Taquaral, [[Itinga]], [[Minas Gerais]], Brazil. Scale at bottom is one inch, with a vertical line at one cm.]]
{{Clear left}}

== See also ==
* [[List of minerals]]

==References==
<references/>
* Klein, Cornelis and Hurlbut, Cornelius S., 1985, ''Manual of Mineralogy'', 20th ed., p.&nbsp;362, {{ISBN|0-471-80580-7}}
*[http://www.mindat.org/min-189.html Mindat with location data]
*[http://webmineral.com/data/Amblygonite.shtml Webmineral data]
*[https://web.archive.org/web/20041009202609/http://mineral.galleries.com/minerals/phosphat/amblygon/amblygon.htm Mineral Galleries]

{{Commons category}}
{{Lithium compounds}}

[[Category:Sodium minerals]]
[[Category:Lithium minerals]]
[[Category:Aluminium minerals]]
[[Category:Phosphate minerals]]
[[Category:Triclinic minerals]]
[[Category:Minerals in space group 2]]
[[Category:Gemstones]]