View source for Kernite

{{short description|Hydrated sodium borate hydroxide mineral}}
{{Infobox mineral
| name        = Kernite
| category    = [[Inoborates]]
| boxwidth    = 
| boxbgcolor  = 
| image       = Kernite - USGS Mineral Specimens 692.jpg
| caption     = 
| formula     = {{chem|Na|2|B|4|O|6|(OH)|2|·3H|2|O}}
| IMAsymbol   = Ker<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   = 273.22 g/mol
| strunz      = 6.DB.05
| system      = [[Monoclinic]] 
| class       = Prismatic (2/m) <br/><small>(same [[H-M symbol]])</small>
| symmetry    = ''P2''<sub>1</sub>/c
| unit cell   = a = 7.0172(2) <br/>b = 9.1582(2) <br/>c = 15.6774(5)&nbsp;[Å] <br/>β = 108.861(2)°; Z&nbsp;=&nbsp;4
| color       = Colorless, white
| habit       = Crystalline - occurs as well-formed coarse sized crystals
| cleavage    = Perfect on [100] and [001], good on [201] 
| fracture    = Splintery
| tenacity    = Brittle 
| mohs        = 2.5-3
| luster      = Vitreous - pearly 
| refractive  = n<sub>α</sub>=1.454, n<sub>β</sub>=1.472, n<sub>γ</sub>=1.488
| opticalprop = Biaxial (-)
| 2V          = 80°
| birefringence = δ =0.0340
| pleochroism = 
| streak      = White
| gravity     = 1.9 - 1.92 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = 
| other       = Non-radioactive, non-fluorescent, non-magnetic
| references  =<ref>[http://webmineral.com/data/Kernite.shtml Kernite WebMineral]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/kernite.pdf Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-2188.html Kernite on Mindat.org]</ref>
}}

'''Kernite''', also known as '''rasorite''', is a hydrated [[sodium]] [[borate]] [[hydroxide]] [[mineral]] with formula {{chem|Na|2|B|4|O|6|(OH)|2|·3H|2|O}}. It is a colorless to white mineral crystallizing in the [[monoclinic crystal system]] typically occurring as prismatic to [[acicular (crystal habit)|acicular crystals]] or granular masses. It is relatively soft with [[Mohs hardness]] of 2.5 to 3 and light with a [[specific gravity]] of 1.91. It exhibits perfect cleavage and a brittle fracture.

Kernite is soluble in cold water and alters to [[tincalconite]] when it dehydrates. It undergoes a non-reversible alteration to [[metakernite]] ({{chem|Na|2|B|4|O|7|·5H|2|O}}) when heated to above 100&nbsp;°C.<ref name=HBM/>

==Occurrence and history==
The mineral occurs in sedimentary [[evaporite]] deposits in arid regions.

Kernite was discovered in 1926 in eastern [[Kern County, California|Kern County]], in [[Southern California]],{{citation needed|date=May 2023}} and later renamed after the county. The location was the [[Pacific Coast Borax Company#U.S. Borax|US Borax Mine]] at [[Boron, California|Boron]] in the western [[Mojave Desert]]. This [[Type specimen (mineralogy)|type material]] is stored at [[Harvard University]], Cambridge, Massachusetts, and the [[National Museum of Natural History]], Washington, D.C.<ref name=HBM/>

The Kern County mine was the only known source of the mineral for a period of time. More recently, kernite is mined in [[Argentina]] and [[Turkey]].<ref name=HBM/>

The largest documented, single crystal of kernite measured 2.44 x 0.9 x 0.9 m<sup>3</sup> and weighed ~3.8 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>

==Uses==
Kernite is used to produce [[borax]] which can be used in a variety of [[soap]]s.

== References ==
{{reflist}}

{{commonscat inline|Kernite|'''Kernite'''}}

{{-}}

[[Category:Sodium minerals]]
[[Category:Inoborates]]
[[Category:Monoclinic minerals]]
[[Category:Minerals in space group 14]]
[[Category:Natural history of Kern County, California]]
[[Category:Natural history of the Mojave Desert]]