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) Environment: Low-temperature precipitate in oxidized iron sulfide deposits. IMA Status: Valid Species (Pre-IMA) 1888 Locality: Antofagasta, from near Caracoles, Sierra Gorda district, Chile. Link to MinDat.org Location Data. Name Origin: Named for Thomas Hohmann (1843-1897), mining engineer of Valparaiso, Chile who discovered the first specimens. Name Pronunciation: Hohmannite + Pronunciation Synonym: Castanite   ICSD 37328   PDF 17-155  

Hohmannite Image

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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 X Ray Diffraction: By Intensity(I/I_o): 7.92(1), 8.69(0.8), 10.4(0.6), Crystal Structure:

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Scordari F , Mineralogical Magazine , 42 (1978) p.144-146, The crystal structure of hohmannite, Fe2(H2O)4[(SO4)2O]*4H2O, and its relationship to amaranite, Fe2(H2O)4[(SO4)2O]*3H2O, Locality: synthetic

 

Physical Properties of Hohmannite

Cleavage: {???} Perfect, {???} Imperfect Color: Brown, Orange brown, Reddish brown. Density: 2.2 Diaphaneity: 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
Ncalc = 1.61 - 1.63 Optical Data: Biaxial (-), a=1.559, b=1.643, g=1.655, bire=0.0960  

Calculated Properties of Hohmannite

Electron Density: Bulk Density (Electron Density)=2.32 gm/cc
note: Specific Gravity of Hohmannite =2.28 gm/cc.
Fermion Index: Fermion Index = 0.0064272507
Boson Index = 0.9935727493 Photoelectric: PE_Hohmannite = 7.83 barns/electron
U=PE_Hohmannite x rElectron Density= 18.16 barns/cc.
Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Hohmannite is Not Radioactive  

Hohmannite Classification

Dana Class: 31.09.04.01 (31)Hydrated Sulfates Containing Hydroxyl or Halogen   (31.09)where (A+ B++) (XO4) Zq·x(H2O)   (31.09.04)Dana Group  

31.09.04.01 Hohmannite Fe2(SO4)2(OH)2•7(H2O) P1 1

Strunz Class: 07.DB.30 07 - SULFATES (SELENATES, TELLURATES)   07.D - Sulfates (selenates, etc.) with additional anions, with H2O   07.DB -With only medium-sized cations; insular octahedra and finite groups  

07.DB.30 Amarantite Fe(SO4)(OH)•3(H2O) P1 1

 

07.DB.30 Hohmannite Fe2(SO4)2(OH)2•7(H2O) P1 1

 

07.DB.30 Metahohmannite Fe2[O(SO4)2]•4(H2O) P1 1

 

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