# Edenite

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Edenite
> Markdown URL: https://mediated.wiki/source/Edenite.md
> Source: https://en.wikipedia.org/wiki/Edenite
> Source revision: 1326150447
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{short description|Amphibole, double chain inosilicate mineral}}
{{Infobox mineral
| name        = Edenite
| category    = [Amphibole](/source/Amphibole) mineral
| boxwidth    = 
| boxbgcolor  = 
| image       = Edenite-188165.jpg
| imagesize   = 
| caption     = Edenite crystal from Bancroft District, Ontario
| formula     = NaCa<sub>2</sub>Mg<sub>5</sub>(Si<sub>7</sub>Al)O<sub>22</sub>(OH)<sub>2</sub>
| IMAsymbol   = Ed<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   = 834.25 g/mol
| strunz      = 9.DE.15
| system      = [Monoclinic](/source/Monoclinic)
| class       = Prismatic (2/m) <br/><small>(same [H-M symbol](/source/H-M_symbol))</small>
| symmetry    = ''C2/m''
| unit cell   = a = 9.83, b = 17.95 <br/>c = 5.3&nbsp;[Å], β = 105.18°; Z&nbsp;=&nbsp;2
| color       = White to gray, pale to dark green, also brown and pale pinkish-brown 
| habit       = Prismatic crystals, fibrous, as reaction rims on pyroxenes
| twinning    = Simple or multiple parallel to {010}
| cleavage    = Good on (110)
| fracture    = Conchoidal
| tenacity    = Brittle
| mohs  = 5–6
| luster      = Vitreous
| refractive  = ''n''<sub>α</sub> =  1.606 – 1.649, ''n''<sub>β</sub> = 1.617 – 1.660, ''n''<sub>γ</sub> = 1.631 – 1.672
| opticalprop = Biaxial (+)
| 2V = 50–82°
| birefringence = δ = 0.025
| pleochroism = Distinct, greens, blue-greens, and yellow-browns
| streak      = White
| gravity     = 3.05–3.37
| density     = 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = Semitransparent
| other       = 
| references  = <ref name=HBM>[http://www.handbookofmineralogy.org/pdfs/edenite.pdf Edenite Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-1351.html Edenite on Mindat.org]</ref><ref name=Webmin>[http://webmineral.com/data/Edenite.shtml Edenite on Webmineral]</ref><ref>[http://pubsites.uws.edu.au/ima-cnmnc/ IMA Master List]</ref>
}}
'''Edenite''' or ''edenitic hornblende'' is a [double chain silicate mineral](/source/Inosilicate) of the [amphibole](/source/amphibole) group with the general chemical composition NaCa<sub>2</sub>Mg<sub>5</sub>(Si<sub>7</sub>Al)O<sub>22</sub>(OH)<sub>2</sub>. Edenite is named for the locality of Edenville, [Orange County, New York](/source/Orange_County%2C_New_York), where it was first described.<ref name=Webmin/>

== Occurrence ==
Edenite has been found primarily in [metamorphic](/source/Metamorphic_rock) rocks, occurring in pods of other magnesium-rich minerals within a [marble](/source/marble) formation or with [garnet](/source/garnet)-rich [lherzolite](/source/lherzolite)s from deep within the Earth's crust.<ref name=j1>{{cite journal|author1=Oberti, R. |author2=Cámara, F. |author3=Della Ventura, G. |author4=Iezzi, G. |author5= Benimoff, A.I. |name-list-style=amp|year=2006|title= Parvo-mangano-edenite, parvo-manganotremolite, and the solid solution between Ca and Mn2+ at the M4 site in amphiboles|journal= American Mineralogist|volume= 91|pages= 526–532|doi=10.2138/am.2006.1905|url=http://rruff.geo.arizona.edu/doclib/am/vol91/AM91_526.pdf|issue=4|bibcode=2006AmMin..91..526O |s2cid=55824304 }}</ref><ref>{{cite journal|author=Yang, J. |year=2003 |title=Relict edenite in a garnet lherzolite from the Chinese Su-Lu UHP metamorphic terrane: Implications for metamorphic history |url=http://www.igcas.ac.cn/admin/uploadfiles/20041028175038_Yang-AM-03.pdf |journal=American Mineralogist |volume=88 |issue=1 |pages=180–188 |doi=10.2138/am-2003-0121 |bibcode=2003AmMin..88..180Y |s2cid=133200002 |url-status=dead |archiveurl=https://web.archive.org/web/20120329105748/http://www.igcas.ac.cn/admin/uploadfiles/20041028175038_Yang-AM-03.pdf |archivedate=2012-03-29 }}</ref>  Thus, finding edenite in the field can indicate high-temperature regional metamorphism of the surrounding rocks.

== Uses and importance==
While edenite is not important for commercial or industrial applications, it is often studied because of its unique chemical substitution properties.  Results from research performed on amphiboles have shown that edenite is particularly suited for fitting chloride anions into its chemical framework.<ref>{{cite journal|author1=Oberti, R. |author2=Hawthorne, F.C. |author3=Cannillo, E. |author4=Cámara, F. |name-list-style=amp|year=2007|title= Long-Range Order in Amphiboles|journal= Reviews in Mineralogy and Geochemistry|volume= 67|issue=1 |pages= 125–171|doi=10.2138/rmg.2007.67.4|bibcode=2007RvMG...67..125O }}</ref> This makes edenite a good candidate for use in [chlorine isotope](/source/Isotopes_of_chlorine) fractionation in amphibole-bearing rocks. Many synthetic variations of edenite are also used in geochemical research to produce a [boron](/source/boron) analogue of [fluoroedenite](/source/fluoro-edenite).<ref>{{cite journal|author1=Oberti, R. |author2=Della Ventura, G. |author3=Cámara, F. |name-list-style=amp|year=2007|title= New Amphibole Compositions: Natural and Synthetic|journal= Reviews in Mineralogy and Geochemistry|volume= 67|issue=1 |pages= 89–124|doi=10.2138/rmg.2007.67.3|bibcode=2007RvMG...67...89O }}</ref>

== Crystal habit ==
Edenite is a member of the [monoclinic](/source/monoclinic) [crystal system](/source/crystal_system) and is in the crystal class 2/m (space group C2/m).<ref name=j1/> This means crystalline edenite is symmetrical around a two-fold rotation axis that is then reflected across a mirror plane perpendicular to the long axis of the mineral.<ref>Klein, C., and Dutrow, B. (2007) The 23rd Edition of the Manual of Mineral Science, John Wiley and Sons, Inc. Hoboken, New Jersey, U.S.</ref>

== Optical properties ==
Edenite is a biaxial positive mineral. When viewed in [thin section](/source/thin_section) with a [petrographic microscope](/source/petrographic_microscope), it is white-gray with pale green [pleochroism](/source/pleochroism) in plane-polarized light. Under crossed polars, its interference colors range from first order gray to first order blue.<ref name=Mindat/>

==References==
{{Reflist}}

Category:Sodium minerals
Category:Calcium minerals
Category:Magnesium minerals
Category:Amphibole group
Category:Hydroxide minerals
Category:Monoclinic minerals
Category:Minerals in space group 12
Category:Minerals described in 1858
Category:Blendes

---
Adapted from the Wikipedia article [Edenite](https://en.wikipedia.org/wiki/Edenite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Edenite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.