Halotrichite Mineral Data
General Halotrichite Information
Chemical Formula:
Fe++Al2(SO4)4•22(H2O)
Composition:
Molecular Weight = 890.40 gm
Aluminum 6.06 % Al 11.45 % Al2 O3
Iron 6.27 % Fe 8.07 % FeO
Hydrogen 4.98 % H 44.51 % H2 O
Sulfur 14.41 % S 35.97 % SO3
Oxygen 68.28 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Fe2+ Al2 (SO4 )4 •22(H2 O)
IMA Status:
Valid Species (Pre-IMA) 1839
Locality:
Link to MinDat.org Location Data.
Name Origin:
From the Latin, halotrichum ="hairy salt."
Name Pronunciation:
Halotrichite + Pronunciation
Synonym:
Feather Alum
Haarsalz
Iron Alum
Halotrichite Image
Images:
Images:
Images:
Halotrichite Crystallography
Axial Ratios:
a:b:c =0.8445:1:0.2543
Cell Dimensions:
a = 20.519, b = 24.297, c = 6.181, Z = 4; beta = 100.9° V = 3,025.94 Den(Calc)= 1.95
Crystal System:
Monoclinic - Sphenoidal H-M Symbol (2) Space Group: P 2
X Ray Diffraction:
By Intensity(I/Io ): 3.5(1), 4.3(1), 4.81(1),
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Physical Properties of Halotrichite
Cleavage:
{010} Indistinct
Color:
Colorless, Green, Gray white, Yellow, White.
Density:
1.78 - 1.9, Average = 1.84
Diaphaneity:
Transparent to translucent
Fracture:
Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Habit:
Encrustations - Forms crust-like aggregates on matrix.
Habit:
Fibrous - Crystals made up of fibers.
Hardness:
1.5-2 - Talc-Gypsum
Luminescence:
Non-fluorescent.
Luster:
Silky
Streak:
white
Optical Properties of Halotrichite
Gladstone-Dale:
CI meas = -0.039 (Excellent) - where the CI = (1-KPDmeas /KC ) CI calc = 0.02 (Excellent) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2489,KPDmeas = 0.2638,KC = 0.2539 Ncalc = 1.45 - 1.5
Optical Data:
Biaxial (-), a=1.48, b=1.486, g=1.49, bire=0.0100, 2V(Calc)=78, 2V(Meas)=35. Dispersion none.
Pleochroism (x):
none.
Pleochroism (y):
none.
Pleochroism (z):
none.
Calculated Properties of Halotrichite
Electron Density:
Bulk Density (Electron Density)=2.03 gm/cc note: Specific Gravity of Halotrichite =1.95 gm/cc.
Fermion Index:
Fermion Index = 0.0027453011 Boson Index = 0.9972546989
Photoelectric:
PEHalotrichite = 2.92 barns/electronU=PEHalotrichite x r Electron Density= 5.93 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Halotrichite is Not Radioactive
Halotrichite Classification
Dana Class:
29.07.03.02 (29) Hydrated Acid and Sulfates
(29.07) where A (B)2 (XO4)4 � x(H2O)
(29.07.03) Halotrichite Group (Monoclinic with 22 H2O)
29.07.03.01 Pickeringite MgAl2(SO4)4•22(H2O) P 2 2
29.07.03.02 Halotrichite FeAl2(SO4)4•22(H2O) P 2 2
29.07.03.03 Apjohnite MnAl2(SO4)4•22(H2O) P 21 /c 2/m
29.07.03.04 Dietrichite (Zn,Fe,Mn)Al2(SO4)4•22(H2O) P 21 /c 2/m
29.07.03.05 Bilinite FeFe2(SO4)4•22(H2O) P 21 /c 2/m
29.07.03.06 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4•22(H2O) Mono
29.07.03.07 Wupatkiite (Co,Mg,Ni)Al2(SO4)4•22(H2O) P 21 /c 2/m
Strunz Class:
07.CB.85 07 - SULFATES (SELENATES, TELLURATES)
07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
07.CB -With only medium-sized cations
07.CB.85 Bilinite FeFe2(SO4)4•22(H2O) P 21 /c 2/m
07.CB.85 Apjohnite MnAl2(SO4)4•22(H2O) P 21 /c 2/m
07.CB.85 Dietrichite (Zn,Fe,Mn)Al2(SO4)4•22(H2O) P 21 /c 2/m
07.CB.85 Halotrichite FeAl2(SO4)4•22(H2O) P 2 2
07.CB.85 Pickeringite MgAl2(SO4)4•22(H2O) P 2 2
07.CB.85 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4•22(H2O) Mono
07.CB.85 Wupatkiite (Co,Mg,Ni)Al2(SO4)4•22(H2O) P 21 /c 2/m
Other Halotrichite Information
See Also:
Links to other databases for Halotrichite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - QUT Mineral Atlas
17 - Ruff.Info
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Print or Cut-and-Paste your Halotrichite Specimen Label here :
Halotrichite
Fe++Al2(SO4)4•22(H2O)
Dana No: 29.07.03.02 Strunz No: 07.CB.85
Locality:
Notes:
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