Fahleite Mineral Data
General Fahleite Information
Chemical Formula:
Zn5CaFe+++2(AsO4)6•14(H2O)
Composition:
Molecular Weight = 1,564.45 gm
Calcium 2.56 % Ca 3.58 % CaO
Zinc 20.90 % Zn 26.01 % ZnO
Iron 7.14 % Fe 10.21 % Fe2 O3
Arsenic 28.73 % As 44.07 % As2 O5
Hydrogen 1.80 % H 16.12 % H2 O
Oxygen 38.86 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Zn5 CaFe3+ 2 (AsO4 )6 •14(H2 O)
Environment:
May be the Zn analog of smolianinovite.
IMA Status:
Approved IMA 1988
Locality:
Tsumeb, Namibia. Link to MinDat.org Location Data.
Name Origin:
Named for Rolfe Fahle of Munich, Germany, a mineral dealer specializing in Tsumeb specimens.
Name Pronunciation:
Fahleite
Fahleite Image
Images:
Fahleite Crystallography
Axial Ratios:
a:b:c =0.546:1:1.8686
Cell Dimensions:
a = 6.4, b = 11.72, c = 21.9, Z = 2; V = 1,642.68 Den(Calc)= 3.16
Crystal System:
Orthorhombic Space Group: Unk
X Ray Diffraction:
By Intensity(I/Io ): 11(1), 22(1), 3.2(0.8),
Physical Properties of Fahleite
Cleavage:
{???} Perfect
Color:
Gray, Gray green, Light green, Straw yellow.
Density:
2.1 - 3.16, Average = 2.63
Diaphaneity:
Transparent
Fracture:
Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).
Habit:
Aggregates - Made of numerous individual crystals or clusters.
Habit:
Fibrous - Crystals made up of fibers.
Hardness:
2 - Gypsum
Luster:
Silky - Pearly
Optical Properties of Fahleite
Gladstone-Dale:
CI meas = -0.173 (Poor) - where the CI = (1-KPDmeas /KC ) CI calc = 0.024 (Excellent) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.202,KPDmeas = 0.2427,KC = 0.207 Ncalc = 1.43 - 1.65
Optical Data:
Biaxial (+), a=1.628, b=1.631, g=1.656, bire=0.0280, 2V(Calc)=40, 2V(Meas)=39.
Calculated Properties of Fahleite
Electron Density:
Bulk Density (Electron Density)=3.04 gm/cc note: Specific Gravity of Fahleite =3.16 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEFahleite = 32.29 barns/electronU=PEFahleite x r Electron Density= 98.08 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Fahleite is Not Radioactive
Fahleite Classification
Dana Class:
40.05.08.02 (40) Hydrated Phosphates, etc
(40.05) with miscellaneous formulae
(40.05.08) Smolianinovite Group
40.05.08.01 Smolianinovite (Co,Ni,Mg,Ca)3(Fe,Al)2(AsO4)4•11(H2O) Unk Ortho
40.05.08.02 Fahleite Zn5CaFe2(AsO4)6•14(H2O) Unk Ortho
40.05.08.03 Barahonaite-(Fe) ! (Ca,Cu,Na,Fe,Al)12Fe2(AsO4)8(OH,Cl)x•nH2O P 2/a or Pa Mono
40.05.08.04 Barahonaite-(Al) ! (Ca,Cu,Na,Fe,Al)12Al2(AsO4)8(OH,Cl)x•nH2O P 2/a or Pa Mono
Strunz Class:
08.CH.55 08 - PHOSPHATES, ARSENATES, VANADATES
08.C - Phosphates without Additional Anions, with H2O
08.CH -With large and medium-sized cations, RO4:H2O < 1:1
08.CH.55 Fahleite Zn5CaFe2(AsO4)6•14(H2O) Unk Ortho
08.CH.55 Smolianinovite (Co,Ni,Mg,Ca)3(Fe,Al)2(AsO4)4•11(H2O) Unk Ortho
08.CH.55 IMA2008-048 ! Zn6(PO4)4•7H2O P1 1
Other Fahleite Information
References:
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Am.Min.,Vol.74,p501,1989)
See Also:
Links to other databases for Fahleite :
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
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Fahleite
Zn5CaFe+++2(AsO4)6•14(H2O)
Dana No: 40.05.08.02 Strunz No: 08.CH.55
Locality:
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