Metahohmannite Mineral Data

Metahohmannite Mineral Data +

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General Metahohmannite Information

Chemical Formula:

Fe+++2[O(SO4)2]·4(H2O)

Composition:

Molecular Weight = 391.88 gm

Iron 28.50 % Fe 40.75 % Fe₂O₃

Hydrogen 2.06 % H 18.39 % H₂O

Sulfur 16.37 % S 40.86 % SO₃

Oxygen 53.08 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₂(O)(SO₄)₂·4(H₂O)

Environment:

Formed rapidly from the dehydration of hohmannite.

IMA Status:

Valid Species (Pre-IMA) 1938

Locality:

Chuquicamata, Quetena, and Alcaparrosa, Chile. Link to MinDat.org Location Data.

Name Origin:

Named after the similarity to hohmannite, with a lower state of hydration.

Metahohmannite Image

Images:

Click Here for Larger Metahohmannite Image

Metahohmannite Hohmannite

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

Images:

Metahohmannite

Comments: Orange-yellow earthy massive metahohmannite with orange hohmannite.
Location: Quetena, Antofagasta, Chile. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Metahohmannite Crystallography

Axial Ratios:

a:b:c =0.752:1:0.7319

Cell Dimensions:

a = 7.3484, b = 9.771, c = 7.1521, Z = 2; alpha = 91.684°, beta = 98.523°, gamma = 86.39° V = 506.63 Den(Calc)= 2.57

Crystal System:

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

Crystal Structure:

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Scordari F , Ventruti G , Gualtieri A F , American Mineralogist , 89 (2004) p.265-370, The structure of metahohmannite, Fe2[O(SO4)2].4H2O,, by in situ synchrotron powder diffraction

Physical Properties of Metahohmannite

Color:

Orange.

Habit:

Pulverulent - Forms a loose, poorly-coherent powdery mass.

Streak:

light yellow

Optical Properties of Metahohmannite

Gladstone-Dale:

CI calc= -0.065 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2803,KC= 0.2632

Optical Data:

Biaxial (+), a=1.709, b=1.718, g=1.734, bire=0.0250, 2V(Calc)=76, 2V(Meas)=70.

Pleochroism (x):

pale yellow.

Pleochroism (y):

reddish yellow.

Pleochroism (z):

reddish brown.

Calculated Properties of Metahohmannite

Electron Density:

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

Fermion Index

Fermion Index = 0.00752
Boson Index = 0.99248

Photoelectric:

PE_{Metahohmannite}= 9.35 barns/electron
U=PE_{Metahohmannite} x r_electron= 24.04 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Metahohmannite is Not Radioactive

Metahohmannite Classification

Dana Class:

31.9.5.1 (31)Hydrated Sulfates Containing Hydroxyl or Halogen

(31.9)where (A+ B++) (XO4) Zq·x(H2O)

(31.9.5)Dana Group

31.9.5.1 Metahohmannite Fe2[O(SO4)2]·4(H2O) P1 1

Strunz Class:

VI/D.01-10 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 Metahohmannite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990, AmMin, v 89, p 265) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Metahohmannite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 - EUROmin Project 5 -Google Images 6 -Google Scholar 7 -Handbook of Mineralogy (UofA) 8 -MinDAT 9 -MinMax(Deutsch) 10 -MinMax(English) 11 -Mineralienatlas (Deutsch) 12 -QUT Mineral Atlas 13 -École des Mines de Paris

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Metahohmannite

Fe+++2[O(SO4)2]·4(H2O)
Dana No: 31.9.5.1 Strunz No: VI/D.01-10
Locality:

Notes: