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

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),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

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

Search for Hohmannite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Hohmannite :

A Bijoux Google Search for Hohmannite
Adam's Minerals Google Search for Hohmannite
Cape Minerals Google Search for Hohmannite
Dakota Matrix Minerals Google Search for Hohmannite
Excalibur Mineral Corp. Google Search for Hohmannite
Exceptional Minerals Google Search for Hohmannite
John Betts Fine Minerals Search for Hohmannite
McDougall Minerals Google Search for Hohmannite
Mineral News Website Link
Rock and Mineral Shows Google Search for Hohmannite
Weinrich Minerals, Inc. Google Search for Hohmannite

Ask about Hohmannite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Hohmannite

Fe+++2(SO4)2(OH)2•7(H2O)
Dana No: 31.09.04.01 Strunz No: 07.DB.30
Locality:

Notes: