Ammonioalunite Mineral Data

Ammonioalunite Mineral Data +

General Ammonioalunite Information

Chemical Formula:

(NH4)Al3(SO4)2(OH)6

Composition:

Molecular Weight = 393.15 gm

Aluminum 20.59 % Al 38.90 % Al₂O₃

Hydrogen 1.03 % H - % Calc as (NH₄)₂O

Hydrogen 1.54 % H 13.75 % H₂O

Sulfur 16.31 % S 40.73 % SO₃

Nitrogen 3.56 % N 6.62 % (NH₄)₂O

Oxygen 56.97 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

(NH₄)Al₃(SO₄)₂(OH)₆

Environment:

Acidic hot springs with temperatures below 100 deg C and low potassium content of the waters.

IMA Status:

Approved IMA 1987

Locality:

The Geysers, Sonoma County, California, USA. Link to MinDat.org Location Data.

Name Origin:

Named for its composition (Ammonia, Al,).

Ammonioalunite Image

Images:

Click Here for Larger Ammonioalunite Image

Ammonioalunite Kaolinite

Comments: White chalky ammonioalunite on darker kaolinite.
Location: Schoeller Mine, Kladno, Stredocesky, Czech Republic. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ammonioalunite Crystallography

Axial Ratios:

a:c = 1:2.55026

Cell Dimensions:

a = 7.013, c = 17.885, Z = 3; V = 761.78 Den(Calc)= 2.57

Crystal System:

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

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

By Intensity(I/I_o): 3.023(1), 5.04(0.93), 2.996(0.5),

Physical Properties of Ammonioalunite

Cleavage:

[???] Good

Color:

Gray white, White.

Density:

2.4

Diaphaniety:

Transparent to Translucent

Habit:

Efflorescences - Crystals covering matrix, generally produced from transpiro-evaporation.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Habit:

Rhombohedral Crystals - Occurs as well-formed crystals showing rhobohedral crystals.

Hardness:

2-3 - Gypsum-Calcite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Ammonioalunite

Gladstone-Dale:

CI meas= -0.246 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.163 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2319,KPDmeas= 0.2483,KC= 0.1994

Optical Data:

Uniaxial (+), w=1.59, e=1.602, bire=0.0120.

Calculated Properties of Ammonioalunite

Electron Density:

r_electron=2.61 gm/cc
note: r_{Ammonioalunite}=2.57 gm/cc.

Fermion Index

Fermion Index = 0.03699
Boson Index = 0.96301

Photoelectric:

PE_{Ammonioalunite}= 1.62 barns/electron
U=PE_{Ammonioalunite} x r_electron= 4.24 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Ammonioalunite is Not Radioactive

Ammonioalunite Classification

Dana Class:

30.2.4.6 (30)Anhydrous Sulfates Containing Hydroxyl or Halogen

(30.2)where (A B)2 XO4 Zq

(30.2.4)Alunite Group (Alunite Subgroup)

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

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

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

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

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

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

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

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

Strunz Class:

VI/B.11-30 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/B - Waterfree sulfates [SO4]2- with unfamiliar anions. mostly big cations

VI/B.11 - Alunite group, Natroalunite - Jarosite - Beaverite

VI/B.11-10 Natroalunite NaAl3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-20 Alunite KAl3(SO4)2(OH)6 R 3m, R 3m Trig

VI/B.11-30 Ammonioalunite (NH4)Al3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-40 Minamiite (Na,Ca,K)Al3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-43 Huangite Ca0.5Al3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-45 Walthierite Ba0.5Al3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-50 Natrojarosite NaFe3(SO4)2(OH)6 R 3m 3m

VI/B.11-60 Jarosite KFe3(SO4)2(OH)6 R 3 3

VI/B.11-65 Dorallcharite (Tl,K)Fe3(SO4)2(OH)6 R 3m 3 2/m

VI/B.11-70 Ammoniojarosite (NH4)Fe3(SO4)2(OH)6 R 3m 3m

VI/B.11-80 Hydronium-jarosite (H3O)Fe3(SO4)2(OH)6 R 3m 3m

VI/B.11-90 Argentojarosite AgFe3(SO4)2(OH)6 R 3m 3m

VI/B.11-100 Plumbojarosite PbFe6(SO4)4(OH)12 R 3m 3 2/m

VI/B.11-110 Osarizawaite PbCuAl2(SO4)2(OH)6 R 3m 3m

VI/B.11-120 Beaverite PbCu(Fe,Al)2(SO4)2(OH)6 R 3m 3m

Other Ammonioalunite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Am.Min.,Vol.73,p145-152,1988)

See Also:

Links to other databases for Ammonioalunite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Ammonioalunite

(NH4)Al3(SO4)2(OH)6
Dana No: 30.2.4.6 Strunz No: VI/B.11-30
Locality:

Notes: