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{{Short description|Fibrous mineral}}
{{Use dmy dates|date=May 2023}}
{{Infobox mineral
| name        = Erionite
| category    = [[Zeolite]] [[mineral]]
| boxwidth    =
| image       = Erionite-348877.jpg
| imagesize   = 260px
| caption     =
| formula     = {{chem|(Na|2|,K|2|,Ca|)|2|Al|4|Si|14|O|36|•15H|2|O}}
| IMAsymbol   = Eri<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>
| system      = Hexagonal
| class       = Dihexagonal dipyramidal (6mmm) <br/>[[H-M symbol]]: (6/m 2/m 2/m)
| symmetry    = ''P6<sub>3</sub>/mmc'' (no. 194)
| color       = White, Green, Gray, Orange
| habit       = Acicular - Occurs as needle-like crystals.
| twinning    =
| cleavage    = [010] Distinct
| fracture    = Splintery
| mohs        = 3.5-4
| luster      = Vitreous - silky
| opticalprop = Uniaxial (-)
| refractive  = n<sub>ω</sub> = 1.4711, n<sub>ε</sub> = 1.474
| birefringence = δ = 0.0191
| streak      = white
| gravity     = 2.09 - 2.13 avg = 2.11
| melt        =
| fusibility  =
| solubility  =
| other       = non-magnetic, non-radioactive, toxic if inhaled 
| references  =<ref>{{Cite web|url=http://webmineral.com/data/Erionite-Na.shtml|title=General Erionite-Na Information|publisher=Mineralogy Database|access-date=2009-07-13}}</ref>
}}

'''Erionite''' is a naturally occurring fibrous mineral that belongs to a group of minerals called [[zeolites]]. It usually is found in [[volcanic ash]] that has been altered by weathering and [[ground water]]. Erionite forms brittle, wool-like fibrous masses in the hollows of rock formations and has an internal molecular structure similar to [[chabazite]]. Some properties of erionite are similar to the properties of [[asbestos]]; however, erionite is not currently regulated by the U.S. [[Environmental Protection Agency]] and there are no occupational exposure limits for erionite fibers.<ref>{{Cite web|url=http://www.ndhealth.gov/EHS/erionite/|title=Erionite|publisher=North Dakota Department of Health|access-date=2009-07-13|archive-url=https://web.archive.org/web/20100612224737/https://www.ndhealth.gov/EHS/Erionite/|archive-date=12 June 2010|url-status=dead}}</ref><ref>{{Cite web| title = Erionite| work = National Cancer Institute| access-date = 2018-08-21| url = https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/erionite| date = 2015-03-20}}</ref> Erionite was first described by A.S. Eakle in 1898, as white woolly fibrous masses in cavities in [[rhyolite]] lava near [[Durkee, Oregon]]. It was originally thought to be another relatively rare zeolite named [[offretite]], which is very similar to erionite in appearance and chemical composition.<ref>{{Cite web|url=http://www.galleries.com/minerals/silicate/erionite/erionite.htm|title=The Mineral Erionite|publisher=Amethyst Galleries' Mineral Gallery|access-date=2009-07-13}}</ref>

==Properties==
The chemical composition of erionite is approximately represented by the formula {{chem|(Na|2|,K|2|,Ca|)|2|Al|4|Si|14|O|36|•15H|2|O}}. It can be differentiated into Erionite-Na, Erionite-K, and Erionite-Ca forms based on the most dominant component. Erionite has a hexagonal, cage-like structure composed of a framework of linked tetrahedra. It consists of white prismatic crystals in radiating groups of crystal fiber. Erionite absorbs up to 20% of its weight in water, has a specific gravity of 2.02 to 2.13, and has gas absorption, ion exchange, and catalytic properties that are highly selective and depend on the molecular size of the absorbed compounds.<ref name="1987a">{{Cite journal | title = Silica and some silicates | journal = IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans | volume = 42 | pages = 1–239 |location=[[Lyon, France]] |year = 1987 | pmid = 2824337 }}</ref> Zeolites, in general, have good thermal stability, rehydration kinetics, and water vapor [[adsorption]] capacity.

==Carcinogenicity==
Erionite is known to be a human carcinogen and is listed by the [[International Agency for Research on Cancer]] as a [[List of IARC Group 1 carcinogens|Group 1 Carcinogen]].<ref name="1987b" /> The prevalence of malignant [[pleural]] and [[peritoneal mesothelioma]] due to erionite exposure in the [[Cappadocia]] region of [[Central Anatolia Region|Central Anatolia]] is very high.<ref name="pmid18520266">{{Cite journal| author = Dikensoy O| title = Mesothelioma due to environmental exposure to erionite in Turkey| journal = Current Opinion in Pulmonary Medicine| volume = 14| issue = 4| pages = 322–5|date=July 2008| pmid = 18520266| doi = 10.1097/MCP.0b013e3282fcea65| s2cid = 31259709}}</ref> Descriptive studies have reported an excess of mortality from [[mesothelioma]] in individuals living in three Turkish villages where there was chronic exposure to erionite; only two cases of mesothelioma occurred in the control village, both in women born elsewhere.<ref name="pmid1848965">{{Cite journal| author = Baris YI| title = Fibrous zeolite (erionite)-related diseases in Turkey| journal = American Journal of Industrial Medicine| volume = 19| issue = 3| pages = 374–8| year = 1991| pmid = 1848965 | doi = 10.1002/ajim.4700190310 }}</ref><ref name="pmid16537834">{{Cite journal|vauthors=Baris YI, Grandjean P | title = Prospective study of mesothelioma mortality in Turkish villages with exposure to fibrous zeolite| journal = Journal of the National Cancer Institute| volume = 98| issue = 6| pages = 414–7|date=March 2006| pmid = 16537834| doi = 10.1093/jnci/djj106| doi-access = free}}</ref> An excess of lung cancer also was reported in two of the three villages contaminated with erionite. Respirable erionite fibers were detected in air samples collected from the affected villages, and lung tissue samples collected from mesothelioma cases contained erionite fibers. A higher proportion of [[ferruginous body|ferruginous bodies]] with a zeolite core were found in inhabitants of the contaminated villages than of those from the two control villages.<ref name="1987a"/><ref name="1987b">{{Cite journal | title = Overall evaluations of carcinogenicity: An updating of IARC Monographs volumes 1 to 42 | journal = IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Supplement / World Health Organization, International Agency for Research on Cancer | volume = 7 | pages = 1–440 | year = 1987 |location=[[Lyon, France]] | pmid = 3482203 }}</ref><ref name="pmid1848965"/> Erionite is reportedly present in the local volcanic [[tuff]].<ref name="pmid16537834"/>

There is sufficient evidence of carcinogenicity of erionite in [[experimental animal]]s. [[Rat]]s exposed to erionite by inhalation or injection ([[intrapleural]] or [[intraperitoneal]]) and [[mice]] exposed by intraperitoneal injection had a high incidence of mesothelioma.<ref name="1987a"/><ref name="1987b"/> Additionally, although carcinogenic properties of erionite have been discovered by investigating the erionite found in Central Anatolia, Turkey, no difference in their carcinogenic capacity has been observed when it was compared to the erionite obtained in North Dakota, USA.<ref>{{cite journal | author = Carbone | year = 2011| title = Erionite exposure in North Dakota and Turkish villages with mesothelioma | journal = PNAS | volume = 108| issue = 33| pages = 13618–23 | doi = 10.1073/pnas.1105887108 |display-authors=etal | pmid=21788493 | pmc=3158231| bibcode = 2011PNAS..10813618C| doi-access = free}}</ref>

==Exposure==
Deposits of fibrous erionite are located in [[Arizona]], [[Nevada]], [[Oregon]], and [[Utah]], as well in urban [[Auckland]] in New Zealand.<ref>{{Cite news |last=Salmond |first=Jennifer |author-link=Jennifer Salmond |last2=Brook |first2=Martin |date=2020-09-23 |title=What lies beneath: is this the new asbestos? |url=https://newsroom.co.nz/2020/09/23/what-lies-beneath-is-this-the-new-asbestos/ |access-date=2024-03-05 |website=Newsroom |language=en-US}}</ref> These zeolite beds may be up to {{convert|15|feet|abbr=on}} thick and may lie in surface outcroppings. Erionite fibers have been detected in samples of road dust in Nevada and U.S. residents of the Intermountain West may be potentially exposed to fibrous erionite in ambient air.<ref name="1987a"/><ref>{{cite journal |author1=Rom W. N. |author2=Casey K. R. |author3=Parry W. T. |author4=Mjaatvedt C. H. |author5=Moatamed F. | year = 1983 | title = Health implications of natural fibrous zeolites for the Intermountain West | journal = Environ Res | volume = 30 | issue = 1| pages = 1–8 | doi=10.1016/0013-9351(83)90159-7|pmid=6299723 |bibcode=1983ER.....30....1R }}</ref> In the summer of 2009 [[North Dakota]] began a study of possible erionite exposure among residents.<ref>{{Cite web|url=http://mesotheliomasos.com/news/north-dakota-erionite-study-finally-underway/ |title=North Dakota Erionite Study Finally Underway |date=16 June 2009 |publisher=Mesothelioma SOS |access-date=2009-07-13 |url-status=dead |archive-url=https://web.archive.org/web/20110714074619/http://mesotheliomasos.com/news/north-dakota-erionite-study-finally-underway/ |archive-date=14 July 2011 }}</ref> Erionite has also been identified in samples from the Tertiary Arikaree Formation in southeast Montana and northwest South Dakota.

In the past, occupational exposure occurred from erionite mining and production operation. Nowadays potential occupational exposure to erionite usually occurs during the production and mining of other zeolites. Erionite was also reported to be a minor component in some commercial zeolites.<ref>Mondale, K. D., F. A. Mumpton and F. F. Aplan. 1978. Beneficiation of Natural Zeolites from [[Bowie, Arizona]]: A Preliminary Report. In ''Natural Zeolites: Occurrences, Properties, Uses''. L. B. Sand and F. A.
Mumpton, eds. New York: Pergamon Press. p. 527-537.</ref> Therefore, the use of other zeolites may result in potential exposure to erionite for the workers and the general population who use the zeolites in a variety of processes and products. Total dust exposures for miners in an open-pit zeolite mine that contained some erionite in Arizona ranged from 0.01 to 13.7&nbsp;mg/m<sup>3</sup>; respirable dust in the mining area was 0.01 to 1.4&nbsp;mg/m<sup>3</sup>.<ref name="1987a"/>
Erionite is held responsible for the high incidence of [[lung cancer]], [[asbestosis]], [[pleural]] mesothelioma and other lung problems in the Turkish village of Tuzkoy near Nevsehir in the popular tourist region of [[Cappadoccia]].<ref>{{Cite web|url=http://www.hurriyetdailynews.com/n.php?n=tuzkoy-village-to-be-burried-in-2012-2010-10-06|title= Burial planned for Turkish 'cancer city' |author=ERİSA DAUTAJ ŞENERDEM |date=6 October 2010 |work=[[Hürriyet Daily News]] |access-date=2012-06-20 }}</ref>

==Gallery==
<gallery>
File:Eriomit Ca kamieniołom Boghill, Glengormley, Belfast, Irlandia Pn..jpg|Erionite-Ca
File:Erionit K, Port Na Boe, Giants Causeway, Antrim Co., Irlandia Pn..jpg|Erionite-K
File:Erionite, Offretite - Malpais Hill, Dudleyville, Pinal Co, Arizona, USA.jpg|Erionite and offretite
File:Erionite-348875.jpg|Erionite in Arizona
File:Erionite-161801.jpg|Erionite in [[Veneto]]
</gallery>

==See also==

* [[Asbestosis]]
* [[Chrysotile]]

==References==
{{Reflist}}

{{USGovernment|url=https://ntp.niehs.nih.gov/ntp/roc/content/profiles/erionite.pdf|title=Erionite}}

==External links==
* [https://archive.today/20121214213841/http://helios.princeton.edu/zeomics/cgi-bin/view_structure.pl?src=iza&id=ERI Structure type ERI]

[[Category:Zeolites]]
[[Category:IARC Group 1 carcinogens]]
[[Category:Hexagonal minerals]]
[[Category:Minerals in space group 194]]