Aluminite Mineral Data

Aluminite Mineral Data +

General Aluminite Information

Chemical Formula:

Al2(SO4)(OH)4·7(H2O)

Composition:

Molecular Weight = 344.16 gm

Aluminum 15.68 % Al 29.63 % Al₂O₃

Hydrogen 5.27 % H 47.11 % H₂O

Sulfur 9.32 % S 23.26 % SO₃

Oxygen 69.73 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Al₂(SO₄)(OH)₄·7(H₂O)

Environment:

Formed in recent or Tertiary clays, marls, and lignites by the action of sulfate solutions derived from the alteration of pyrite or marcasite on aluminous silicates.

IMA Status:

Valid Species (Pre-IMA) 1807

Locality:

Halle, Saxony, Germany. Link to MinDat.org Location Data.

Name Origin:

Named after its chemical composition.

Synonym:

ICSD 2234

PDF 43-669

Websterite

Aluminite Image

Images:

Aluminite

Comments: Snow-white, very pure nodules of aluminite.
Location: Newhaven, Sussex, Great Britain. Scale: 5.5 x 3 cm.
© John Veevaert

Aluminite Crystallography

Axial Ratios:

a:b:c =0.4774:1:0.7508

Cell Dimensions:

a = 7.44, b = 15.583, c = 11.7, Z = 4; beta = 110.18° V = 1,273.20 Den(Calc)= 1.80

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 8.977(1), 7.791(0.87), 4.696(0.48),

Crystal Structure:

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Sabelli C , Ferroni R T , Acta Crystallographica, Section B , 34 (1978) p.2407-2412, The crystal structure of aluminite, Note: anisotropic displacement factors from ICSD

Physical Properties of Aluminite

Cleavage:

None

Color:

White, Grayish white.

Density:

1.66 - 1.7, Average = 1.68

Diaphaniety:

Opaque

Fracture:

Earthy - Dull, clay-like fractures with no visible crystalline affinities, (e.g. howlite).

Habit:

Botryoidal - "Grape-like" rounded forms (e.g.. malachite).

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Habit:

Mammillary - Larger "breast-like" rounded forms resembling botryoidal (e.g. malachite).

Hardness:

1 - Talc

Luminescence:

Fluorescent.

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Aluminite

Gladstone-Dale:

CI meas= -0.052 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.018 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.258,KPDmeas= 0.2764,KC= 0.2627

Optical Data:

Biaxial (+), a=1.459, b=1.464, g=1.47, bire=0.0110, 2V(Calc)=86, 2V(Meas)=90. Dispersion none.

Pleochroism (x):

colorless.

Calculated Properties of Aluminite

Electron Density:

r_electron=1.88 gm/cc
note: r_Aluminite=1.80 gm/cc.

Fermion Index

Fermion Index = 0.00104
Boson Index = 0.99896

Photoelectric:

PE_Aluminite= 1.15 barns/electron
U=PE_Aluminite x r_electron= 2.16 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Aluminite is Not Radioactive

Aluminite Classification

Dana Class:

31.7.4.1 (31)Hydrated Sulfates Containing Hydroxyl or Halogen

(31.7)where (A+ B++)2 (XO4) Zq·x(H2O)

(31.7.4)Dana Group

31.7.4.1 Aluminite Al2(SO4)(OH)4·7(H2O) P 2₁/c 2/m

Strunz Class:

VI/D.06-40 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/D - Water-bearing sulfates with unfamiliar anions. cations of medium size

VI/D.06 - Aluminite series, Jurbanite - Zaherite

VI/D.06-10 Jurbanite Al(SO4)(OH)·5(H2O) P 2₁/n 2/m

VI/D.06-20 Khademite Al(SO4)F·5(H2O) Pcab 2/m 2/m 2/m

VI/D.06-20* Rostite AlSO4(OH,F)·5(H2O) Pcba 2/m 2/m 2/m

VI/D.06-30 Meta-aluminite Al2(SO4)(OH)4·5(H2O) P 2₁/c ? 2/m

VI/D.06-40 Aluminite Al2(SO4)(OH)4·7(H2O) P 2₁/c 2/m

VI/D.06-50 Basaluminite Al4(SO4)(OH)10·5(H2O) P 2₁ 2

VI/D.06-60 Felsobanyaite Al4(SO4)(OH)10·5(H2O) Unk Hex

VI/D.06-70 Hydrobasaluminite Al4(SO4)(OH)10·12-36(H2O) Unk. Mono

VI/D.06-80 Zaherite Al12(SO4)5(OH)26·20H20 P1 or P1 Tri

Other Aluminite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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Aluminite

Al2(SO4)(OH)4·7(H2O)
Dana No: 31.7.4.1 Strunz No: VI/D.06-40
Locality:

Notes: