Faheyite Mineral Data

General Faheyite Information

Chemical Formula:

(Mn,Mg)Fe+++2Be2(PO4)4•6(H2O)

Composition:

Molecular Weight = 664.98 gm

Magnesium 0.91 % Mg 1.52 % MgO

Manganese 6.20 % Mn 8.00 % MnO

Beryllium 2.71 % Be 7.52 % BeO

Iron 16.80 % Fe 24.01 % Fe₂O₃

Phosphorus 18.63 % P 42.69 % P₂O₅

Hydrogen 1.82 % H 16.25 % H₂O

Oxygen 52.93 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺_0.75Mg_0.25Fe³⁺₂Be₂(PO₄)₄•6(H₂O)

Environment:

Late-stage secondary mineral in a complex granite pegmatite.

IMA Status:

Valid Species (Pre-IMA) 1953

Locality:

Sapucaia pegmatite mine, about 50 km east-southeast of Governador Valadares, Minas Gerais, Brazil. Link to MinDat.org Location Data.

Name Origin:

Named for Joseph John Fahey (1901-1980), American analytical chemist, U.S. Geological Survey, Washington, D.C., USA.

Name Pronunciation:

Faheyite

Faheyite Image

Images:

Faheyite

Comments: Cluster of faheyite microcrystals, 0.1 cm across.
Location: Roosevelt group (Rough Rider), Custer, Custer District, Custer Co., South Dakota, USA. Scale: Picture Size 15 mm.
© Jeff Weissman / Photographic Guide to Mineral Species

Faheyite Crystallography

Axial Ratios:

a:c = 1:1.69671

Cell Dimensions:

a = 9.43, c = 16, Z = 3; V = 1,232.18 Den(Calc)= 2.69

Crystal System:

Hexagonal - Trapezohedral H-M Symbol (6 2 2) Space Group: P 6₂22

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 5.72(1), 7.28(0.9), 3.244(0.6),

Physical Properties of Faheyite

Cleavage:

{???} Perfect

Color:

Blue white, Brownish white, White.

Density:

2.66

Streak:

white

Optical Properties of Faheyite

Gladstone-Dale:

CI meas= 0.019 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.03 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2385,KPDmeas= 0.2412,KC= 0.2459
Ncalc = 1.65 - 1.66

Optical Data:

Uniaxial (+), w=1.631, e=1.652, bire=0.0210.

Calculated Properties of Faheyite

Electron Density:

Bulk Density (Electron Density)=2.64 gm/cc
note: Specific Gravity of Faheyite =2.66 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Faheyite= 7.46 barns/electron
U=PE_Faheyite x rElectron Density= 19.69 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Faheyite is Not Radioactive

Faheyite Classification

Dana Class:

40.05.03.01 (40)Hydrated Phosphates, etc

(40.05)with miscellaneous formulae

(40.05.03)Dana Group

40.05.03.01 Faheyite (Mn,Mg)Fe2Be2(PO4)4•6(H2O) P 6₂22 6 2 2

Strunz Class:

08.CA.15 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CA -With small and large/medium cations

08.CA.15 Faheyite (Mn,Mg)Fe2Be2(PO4)4•6(H2O) P 6₂22 6 2 2

Other Faheyite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Faheyite :
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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Print or Cut-and-Paste your Faheyite Specimen Label here :

Faheyite

(Mn,Mg)Fe+++2Be2(PO4)4•6(H2O)
Dana No: 40.05.03.01 Strunz No: 08.CA.15
Locality:

Notes:

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