Faheyite
A valid IMA mineral species - grandfathered
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About Faheyite
Joseph John Fahey
Formula:
Be2Mn2+Fe3+2(PO4)4 · 6H2O
Colour:
White, bluish-white, brownish-white
Lustre:
Sub-Vitreous, Silky
Hardness:
3
Specific Gravity:
2.66
Crystal System:
Trigonal
Name:
Named in 1953 by Marie Louise Lindberg (Smith) and Kiguma Jack Murata in honor of Joseph John Fahey [July 30, 1901 Messina, New York, USA - June 29, 1980 Adelphi, Maryland, USA], mineral chemist at the U. S. Geological Survey, Menlo Park, California, USA. Fahey named several minerals including bradleyite, edgarbaileyite, and wherryite
White silky needles
Unique Identifiers
Mindat ID:
1435
Long-form identifier:
mindat:1:1:1435:5
GUID
(UUID V4):
(UUID V4):
dcaf35fe-dca6-47a6-8e50-cb7677e63672
IMA Classification of Faheyite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Faheyite
8.CA.15
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
40.5.3.1
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
19.3.13
19 : Phosphates
3 : Phosphates of Be and Mg
19 : Phosphates
3 : Phosphates of Be and Mg
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Fah | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Faheyite
Sub-Vitreous, Silky
Transparency:
Transparent
Colour:
White, bluish-white, brownish-white
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect // to c
Perfect // to c
Fracture:
Splintery
Density:
2.66 g/cm3 (Measured) 2.670 g/cm3 (Calculated)
Optical Data of Faheyite
Type:
Uniaxial (+)
RI values:
nω = 1.631 nε = 1.652
Birefringence:
0.020
Max Birefringence:
δ = 0.021
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Optical Extinction:
Parallel
Pleochroism:
Non-pleochroic
Chemistry of Faheyite
Mindat Formula:
Be2Mn2+Fe3+2(PO4)4 · 6H2O
Common Impurities:
Na
Crystallography of Faheyite
Crystal System:
Trigonal
Class (H-M):
3 2 - Trapezohedral
Space Group:
P31 2 1
Cell Parameters:
a = 9.404(7) Å, c = 15.920(11) Å
Ratio:
a:c = 1 : 1.693
Unit Cell V:
1219 ų
Z:
3
Morphology:
Individual fibers of faheyite average about 0.08 mm. in length and 0.01 mm. in thickness. The singly fibers may be terminated by pyramid faces.
Comment:
Previously thought to have space group P6322.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.28 Å | (90) |
| 5.72 Å | (100) |
| 3.96 Å | (50) |
| 3.24 Å | (60) |
| 3.09 Å | (60) |
| 3.03 Å | (60) |
| 2.72 Å | (30) |
| 2.67 Å | (30) |
Comments:
ICDD 6-109
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Faheyite
General Appearance of Type Material:
In vugs as white, bluish white, or brownish white tufted fibers coating other minerals.
Geological Setting of Type Material:
Late-stage phosphate mineralization in granite pegmatite
Associated Minerals at Type Locality:
Synonyms of Faheyite
Other Language Names for Faheyite
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.CA. | Davidlloydite | Zn3(AsO4)2 · 4H2O |
| 8.CA. | Apexite | NaMg(PO4) · 9H2O |
| 8.CA. | Brandãoite | BeAl2(PO4)2(OH)2(H2O)5 |
| 8.CA.05 | Fransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.05 | Parafransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.10 | Ehrleite | Ca4Be3Zn2(PO4)6 · 9H2O |
| 8.CA.20 | Gainesite | Na(Na,K)(Be,Li)Zr2(PO4)4 · 1.5-2H2O |
| 8.CA.20 | Mccrillisite | NaCs(Be,Li)Zr2(PO4)4 · 1-2H2O |
| 8.CA.20 | Selwynite | NaK(Be,Al)Zr2(PO4)4 · 2H2O |
| 8.CA.25 | Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O |
| 8.CA.30 | Hopeite | ZnZn2(PO4)2 · 4H2O |
| 8.CA.30 | Arsenohopeite | Zn3(AsO4)2 · 4H2O |
| 8.CA.30 | Nizamoffite | Mn2+Zn2(PO4)2(H2O)4 |
| 8.CA.30 | Unnamed (Mg-analogue of Hopeite) | Mg3(PO4)2 · 4H2O |
| 8.CA.35 | Warikahnite | Zn3(AsO4)2 · 2H2O |
| 8.CA.40 | Phosphophyllite | Zn2Fe(PO4)2 · 4H2O |
| 8.CA.42 | Steinmetzite | Zn2Fe3+(PO4)2(OH) · 3H2O |
| 8.CA.45 | Parascholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.45 | Scholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.50 | Keyite | Cu2+3Zn4Cd2(AsO4)6 · 2H2O |
| 8.CA.55 | Pushcharovskite | K0.6Cu18[AsO2(OH)2]4[AsO3OH]10(AsO4)(OH)9.6 · 18.6H2O |
| 8.CA.60 | Prosperite | Ca2Zn4(AsO4)4 · H2O |
| 8.CA.65 | Gengenbachite | KFe3+3(PO3OH)4[PO2(OH)2]2 · 6H2O |
| 8.CA.70 | Parahopeite | Zn3(PO4)2 · 4H2O |
| 8.CA.70 | Reaphookhillite | MgZn2(PO4)2 · 4H2O |
| 8.CA.75 | Stergiouite | CaZn2(AsO4)2 · 4H2O |
| 8.CA.80 | Limousinite | BaCa[Be4P4O16] · 6H2O |
| 8.CA.85 | Minjiangite | BaBe2(PO4)2 |
| 8.CA.85 | Wilancookite | (Ba5Li2◻)Ba6Be24P24O96 · 26H2O |
Fluorescence of Faheyite
Not fluorescent
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Faheyite
mindat.org URL:
https://www.mindat.org/min-1435.html
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References for Faheyite
Reference List:
Lindberg, Marie Louise, Murata, K. J. (1953) Faheyite, a new phosphate mineral from the Sapucaia pegmatite mine, Minas Gerais, Brazil. American Mineralogist, 38 (3-4) 263-270
Localities for Faheyite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Brazil (TL) | |
| Rocks & Minerals: 62: 318. +1 other reference |
South Africa | |
| O. von Knorring: "Some mineralogical et al. (1985) |
USA | |
| Robinson et al.: Miner. Rec. 23:423-437 (1992) |
Quick NavTopAbout FaheyiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Roosevelt group, Custer, Custer Mining District, Custer County, South Dakota, USA