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Nelenite

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Nelenite
Nelenite (brown) andfranklinite(metallic, black), from Franklin, Franklin Mining District, Sussex County, New Jersey, US
General
CategoryPhyllosilicate
Formula
(repeating unit)
(Mn,Fe)16As3Si12O36(OH)17or
(Mn,Fe)16(Si12O30)(OH)14[As3+3O6(OH)3]
IMA symbolNln[1]
Strunz classification9.EE.15
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(sameH-M symbol)
Space groupC2/m
Unit cella = 23.24, b = 13.41
c = 7.38 [Å]; β = 105.21°; Z = 2
Identification
ColorLight to medium brown
Crystal habitCoarsely granular to massive
CleavagePerfect on {0001}
Mohs scalehardness5
LusterVitreous, resinous
StreakLight brown
DiaphaneityTransparent
Specific gravity3.46
Optical propertiesUniaxial (-)
Refractive indexnω= 1.718 nε= 1.700
Birefringenceδ = 0.018
PleochroismVisible ε = colorless and ω = light brown
References[2][3][4]

Neleniteis a raremanganeseironphyllosilicatearsenatemineral found inFranklin Furnace,New Jersey.

Its chemical formula is(Mn,Fe)16As3Si12O36(OH)17or(Mn,Fe)16(Si12O30)(OH)14[As3+3O6(OH)3][2]

Discovery and occurrence

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It was first describe in 1984 for an occurrence in the Trotter Mine, Franklin Mining District,Sussex County, New Jersey.It was named for Joseph A. Nelen of the Smithsonian Institution.[2][4]It has also been reported fromMontgomery County, Virginiaand theSuceavadistrict ofRomania.[2]At thetype localityin New Jersey it occurs associated withactinolite,calcite,willemite,tirodite,rhodonite,apatite,lennilenapeite, stilpnomelane,microclineandtalc.[4]

References

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  1. ^Warr, L.N. (2021)."IMA–CNMNC approved mineral symbols".Mineralogical Magazine.85(3): 291–320.Bibcode:2021MinM...85..291W.doi:10.1180/mgm.2021.43.S2CID235729616.
  2. ^abcdMindat.org - Nelenite
  3. ^Webmineral - Nelenite
  4. ^abcHandbook of Mineralogy - Nelenite