Hohmannite Mineral Data

Hohmannite Mineral Data +

General Hohmannite Information

Chemical Formula:

Fe+++2(SO4)2(OH)2·7(H2O)

Composition:

Molecular Weight = 463.94 gm

Iron 24.07 % Fe 34.42 % Fe₂O₃

Hydrogen 3.48 % H 31.06 % H₂O

Sulfur 13.82 % S 34.51 % SO₃

Oxygen 58.63 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₂(SO₄)₂(OH)₂·7(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1888

Locality:

Link to MinDat.org Location Data.

Synonym:

Castanite

ICSD 37328

PDF 17-155

Hohmannite Image

Images:

Hohmannite Metahohmannite

Comments: Orange opaque prismatic microcrystals of hohmannite mixed with yellow metahohmanite.
Location: Chuquicamata, Antofagasta, Chile. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hohmannite Crystallography

Axial Ratios:

a:b:c =0.8318:1:0.659

Cell Dimensions:

a = 9.05, b = 10.88, c = 7.17, Z = 2; alpha = 90.15°, beta = 90.58°, gamma = 107° V = 675.10 Den(Calc)= 2.28

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 7.92(1), 8.69(0.8), 10.4(0.6),

Physical Properties of Hohmannite

Cleavage:

[???] Perfect, [???] Imperfect

Color:

Brown, Orange brown, Reddish brown.

Density:

2.2

Diaphaniety:

Transparent to Translucent

Hardness:

3 - Calcite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

orange

Optical Properties of Hohmannite

Gladstone-Dale:

CI meas= -0.023 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.013 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2715,KPDmeas= 0.2814,KC= 0.2751

Optical Data:

Biaxial (-), a=1.559, b=1.643, g=1.655, bire=0.0960

Calculated Properties of Hohmannite

Electron Density:

r_electron=2.32 gm/cc
note: r_Hohmannite=2.28 gm/cc.

Fermion Index

Fermion Index = 0.00642
Boson Index = 0.99358

Photoelectric:

PE_Hohmannite= 7.83 barns/electron
U=PE_Hohmannite x r_electron= 18.16 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Hohmannite is Not Radioactive

Hohmannite Classification

Dana Class:

31.9.4.1 (31)Hydrated Sulfates Containing Hydroxyl or Halogen

(31.9)where (A+ B++) (XO4) Zq·x(H2O)

(31.9.4)Dana Group

31.9.4.1 Hohmannite Fe2(SO4)2(OH)2·7(H2O) P1 1

Strunz Class:

VI/D.01-50 VI - Sulfates,Chromates,Molybdates and Tungstates

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

VI/D.01 - Metahohmannite - Xitieshanite series

VI/D.01-10 Metahohmannite Fe2[O(SO4)2]·4(H2O) P1 1

VI/D.01-20 Butlerite Fe(SO4)(OH)·2(H2O) P 2₁/m 2/m

VI/D.01-30 Parabutlerite Fe(SO4)(OH)·2(H2O) Pmnb 2/m 2/m 2/m

VI/D.01-40 Amarantite Fe(SO4)(OH)·3(H2O) P1 1

VI/D.01-50 Hohmannite Fe2(SO4)2(OH)2·7(H2O) P1 1

VI/D.01-60 Fibroferrite Fe(SO4)(OH)·5(H2O) R 3 3

VI/D.01-70 Xitieshanite Fe(SO4)(OH)·7(H2O) P 2₁/a 2/m

Other Hohmannite Information

References:

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

See Also:

Links to other databases for Hohmannite :
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 - WWW-MINCRYST 13 -École des Mines de Paris

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Print or Cut-and-Paste your Hohmannite Specimen Label here :

Hohmannite

Fe+++2(SO4)2(OH)2·7(H2O)
Dana No: 31.9.4.1 Strunz No: VI/D.01-50
Locality:

Notes: