Natroalunite Mineral Data

General Natroalunite Information

Chemical Formula:

NaAl3(SO4)2(OH)6

Composition:

Molecular Weight = 398.11 gm

Sodium 5.77 % Na 7.78 % Na₂O

Aluminum 20.33 % Al 38.42 % Al₂O₃

Hydrogen 1.52 % H 13.58 % H₂O

Sulfur 16.11 % S 40.22 % SO₃

Oxygen 56.26 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaAl₃(SO₄)₂(OH)₆

Environment:

Formed by solfataric or hydrothermal sulfate-bearing solutions reacting with clays.

IMA Status:

Valid Species (Pre-IMA) 1911

Locality:

National Belle mine, Colorado, USA Link to MinDat.org Location Data.

Name Origin:

Named as the sodium, natrium, analog of alunite.

Synonym:

ICSD 31244

Natro-alunite - Renamed Natroalunite by Mineralogical Record, v39 (2008), p131

PDF 41-1467

Natroalunite Image

Images:

Natroalunite

Comments: Pure white porcelaneous massive natroalunite.
Location: Sugarloaf Butte, Quartzite, La Paz County, Arizona, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Natroalunite Crystallography

Axial Ratios:

a:c = 1:2.39931

Cell Dimensions:

a = 6.977, c = 16.74, Z = 3; V = 705.71 Den(Calc)= 2.81

Crystal System:

Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.96(1), 4.9(0.75), 2.97(0.7),

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Forms: ( 0 1 2) ( 0 0 1)

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Physical Properties of Natroalunite

Cleavage:

{1110} Distinct

Color:

White, Grayish, Yellowish, Reddish, Brownish.

Density:

2.6 - 2.9, Average = 2.75

Diaphaneity:

Transparent to Subopaque

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Natroalunite

Gladstone-Dale:

CI meas= 0.005 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.027 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.206,KPDmeas= 0.2105,KC= 0.2117
Ncalc = 1.55 - 1.61

Optical Data:

Uniaxial (+), w=1.568, e=1.59, bire=0.0220.

Calculated Properties of Natroalunite

Electron Density:

Bulk Density (Electron Density)=2.76 gm/cc
note: Specific Gravity of Natroalunite =2.75 gm/cc.

Fermion Index:

Fermion Index = 0.0014805445
Boson Index = 0.9985194555

Photoelectric:

PE_Natroalunite= 1.69 barns/electron
U=PE_Natroalunite x rElectron Density= 4.67 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Natroalunite is Not Radioactive

Natroalunite Classification

Dana Class:

30.02.04.02 (30)Anhydrous Sulfates Containing Hydroxyl or Halogen

(30.02)where (A B)2 XO4 Zq

(30.02.04)Alunite Group (Alunite Subgroup)

30.02.04.01 Alunite KAl3(SO4)2(OH)6 R 3m, R 3m Trig

30.02.04.02 Natroalunite NaAl3(SO4)2(OH)6 R 3m 3 2/m

30.02.04.03 Schlossmacherite (H3O,Ca)Al3(AsO4,SO4)2(OH)6 R 3m 3 2/m

30.02.04.04 Osarizawaite PbCuAl2(SO4)2(OH)6 R 3m 3m

30.02.04.05 Minamiite (Na,Ca,K)Al3(SO4)2(OH)6 R 3m 3 2/m

30.02.04.06 Ammonioalunite (NH4)Al3(SO4)2(OH)6 R 3m 3 2/m

30.02.04.07 Walthierite Ba0.5Al3(SO4)2(OH)6 R 3m 3 2/m

30.02.04.08 Huangite Ca0.5Al3(SO4)2(OH)6 R 3m 3 2/m

Strunz Class:

07.BC.10 07 - SULFATES (SELENATES, TELLURATES)

07.B - Sulfates (selenates, etc.) with Additional Anions, without H2O

07.BC -With medium-sized and large cations

07.BC.10 Alunite KAl3(SO4)2(OH)6 R 3m, R 3m Trig

07.BC.10 Ammonioalunite (NH4)Al3(SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Ammoniojarosite (NH4)Fe3(SO4)2(OH)6 R 3m 3m

07.BC.10 Beaverite PbCu(Fe,Al)2(SO4)2(OH)6 R 3m 3m

07.BC.10 Argentojarosite AgFe3(SO4)2(OH)6 R 3m 3m

07.BC.10 Huangite Ca0.5Al3(SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Dorallcharite (Tl,K)Fe3(SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Jarosite KFe3(SO4)2(OH)6 R 3 3

07.BC.10 Hydroniumjarosite (H3O)Fe3(SO4)2(OH)6 R 3m 3m

07.BC.10 Minamiite (Na,Ca,K)Al3(SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Natrojarosite NaFe3(SO4)2(OH)6 R 3m 3m

07.BC.10 Natroalunite NaAl3(SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Osarizawaite PbCuAl2(SO4)2(OH)6 R 3m 3m

07.BC.10 Plumbojarosite PbFe6(SO4)4(OH)12 R 3m 3 2/m

07.BC.10 Schlossmacherite (H3O,Ca)Al3(AsO4,SO4)2(OH)6 R 3m 3 2/m

07.BC.10 Walthierite Ba0.5Al3(SO4)2(OH)6 R 3m 3 2/m

Other Natroalunite Information

References:

NAME( AntBidBlaNic5) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Natroalunite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Glendale Community College
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Natroalunite

NaAl3(SO4)2(OH)6
Dana No: 30.02.04.02 Strunz No: 07.BC.10
Locality:

Notes:

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