Editing Natron (section)

{{Short description|Carbonate mineral}}
{{Other uses}}
{{More citations needed|date=August 2022}}

{{Infobox mineral
| name        = Natron
| category    = [[Carbonate mineral]]
| boxwidth    = 
| boxbgcolor  = 
| image       = Emi Koussi crater natron.jpg
| imagesize   = 
| alt         = 
| caption     = Natron deposits in the Era Kohor crater in the [[Tibesti Mountains]], [[Chad]]
| formula     = Na<sub>2</sub>CO<sub>3</sub>·10H<sub>2</sub>O
| IMAsymbol   = Nt<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      = 5.CB.10
| dana        = 15.01.02.01
| system      = [[Monoclinic]]
| class       = Prismatic (2/m) <br/><small>(same [[H-M symbol]])</small>
| symmetry    = ''P''2/m
| unit cell   = a = 12.75 Å, b = 9 Å, c = 12.6 Å<br>β = 115.85°
| colour      = Colourless to white, greyish, yellowish; colourless in transmitted light.
| habit       = crystalline, granular, and columnar crusts
| twinning    = on {001}
| cleavage    = On {001} distinct; on {010} imperfect; on {110} in traces.
| fracture    = Conchoidal
| tenacity    = Brittle
| mohs        = 1 – 1.5
| lustre      = Vitreous
| streak      = White
| diaphaneity = Transparent to translucent
| gravity     = 1.478
| density     = 
| polish      = 
| opticalprop = Biaxial (−)
| refractive  = n<sub>α</sub> = 1.405 n<sub>β</sub> = 1.425 n<sub>γ</sub> = 1.440
| birefringence = δ = 0.035
| pleochroism = 
| 2V          = Measured: 71° , Calculated: 80°
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence= 
| absorption  =
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = Soluble in water
| other       = 
| alteration  = 
| references  = <ref name=Mindat>{{Cite web|title=Natron Mindat|url=https://www.mindat.org/min-2858.html|access-date=2022-11-28|website=mindat.org}}</ref><ref name=Handbook>{{Cite web|title=Natron Handbook|url=http://rruff.info/doclib/hom/natron.pdf|access-date=2022-11-28}}</ref><ref name=Webmin>{{Cite web |title=Natron Mineral Data |url=https://webmineral.com/data/Natron.shtml |access-date=2022-11-26 |website=webmineral.com}}</ref>
}}
'''Natron''' is a naturally occurring mixture of [[sodium carbonate]] decahydrate ([[sodium carbonate|Na<sub>2</sub>CO<sub>3</sub>]]·10H<sub>2</sub>O, a kind of [[soda ash]]) and around 17% [[sodium bicarbonate]] (also called baking soda, NaHCO<sub>3</sub>) along with small quantities of [[sodium chloride]] and [[sodium sulfate]]. Natron is white to colourless when pure, varying to gray or yellow with impurities. Natron deposits are sometimes found in saline lake beds which arose in arid environments. Throughout history natron has had many practical applications that continue today in the wide range of modern uses of its constituent mineral components.

In modern [[mineralogy]] the term ''natron'' has come to mean only the sodium carbonate decahydrate (hydrated soda ash) that makes up most of the historical salt.

[[File:Natron deposits, Trou au Natron, Chad.jpg|thumb|Natron deposits, Trou au Natron, Tibesti, Chad]]