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Phosphofibrite

A valid IMA mineral species
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01751440017271925819765.jpg
Phosphofibrite, etc.

Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany
01516340017271925841100.jpg
Phosphofibrite, etc.

Silver Coin Mine, Valmy, Iron Point Mining District, Humboldt County, Nevada, USA
01751440017271925819765.jpg
Phosphofibrite, etc.

Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany
01516340017271925841100.jpg
Phosphofibrite, etc.

Silver Coin Mine, Valmy, Iron Point Mining District, Humboldt County, Nevada, USA
01751440017271925819765.jpg
Phosphofibrite, etc.

Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany
01516340017271925841100.jpg
Phosphofibrite, etc.

Silver Coin Mine, Valmy, Iron Point Mining District, Humboldt County, Nevada, USA
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About PhosphofibriteHide

Formula:
(H2O,K)3.5Fe8(PO4)6(OH)7 · 5H2O
Previously given as K<0.5(Fe3+,Cu)8(PO4)6(OH)7·7H2O.
Colour:
Yellow to yellowish green
Lustre:
Vitreous
Hardness:
4
Crystal System:
Monoclinic
Name:
Name for the composition (phosphate) and the fibrous habit.
See also meurigite-K and meurigite-Na.


Unique IdentifiersHide

Mindat ID:
3200
Long-form identifier:
mindat:1:1:3200:7

IMA Classification of PhosphofibriteHide

IMA status:
Approved
IMA Formula:
(H2O,K)3.5Fe3+8(PO4)6(OH)7(H2O)5
Approval year:
1982

Classification of PhosphofibriteHide

Strunz-mindat (2026):
8.DJ.20

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
J : With large and medium-sized cations, (OH, etc.):RO4 = 1:1
Dana 8th ed.:
42.13.14.3

42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
13 : Miscellaneous
Hey's CIM Ref.:
19.2.14

19 : Phosphates
2 : Phosphates of Cu

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
PfbIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of PhosphofibriteHide

Lustre:
Vitreous
Transparency:
Translucent
Colour:
Yellow to yellowish green
Hardness:
4 on Mohs scale

Optical Data of PhosphofibriteHide

Type:
Biaxial (-)
RI values:
nα = 1.755 nγ = 1.79
Max. Birefringence:
δ = 0.035
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure - the conoscopic view for a grain cut perpendicular to the acute bisectrix, using this mineral's 2V. The two small white dots mark the melatopes - the points where the two optic axes emerge - and are shown only when they fall within the field of view. The coloured bands are isochromatics, and the dark bands are isogyres.

Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.

No measured or calculated 2V is on file for this mineral, so the value used here (89°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
distinct to strong

Chemistry of PhosphofibriteHide

Mindat Formula:
(H2O,K)3.5Fe8(PO4)6(OH)7 · 5H2O

Previously given as K<0.5(Fe3+,Cu)8(PO4)6(OH)7·7H2O.
Element Weights:
Element% weight
O49.037 %
Fe34.666 %
P14.420 %
H1.877 %

Calculated from ideal end-member formula.
O
Fe
P
H
Elements listed:
Fe, H, K, O, P - search for minerals with similar chemistry

Crystallography of PhosphofibriteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 29.02 Å, b = 5.20 Å, c = 19.72 Å
β = 107.04°
Ratio:
a:b:c = 5.581 : 1 : 3.792
Unit Cell V:
2,845.19 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space group C2/c; refined from powder diffraction film data; originally assumed to be orthorhombic, space group Pbmn or Pnmn.

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4b: Highly evolved igneous rocks>3.0
34 : Complex granite pegmatites
Stage 7: Great Oxidation Event<2.4
47a : [Near-surface hydration of prior minerals]
47c : [Carbonates, phosphates, borates, nitrates]

Type Occurrence of PhosphofibriteHide

Synonyms of PhosphofibriteHide

Other Language Names for PhosphofibriteHide

Common AssociatesHide

Associations Based on Photo Data:
2 photos of Phosphofibrite associated with LeucophosphiteKFe3+2(PO4)2(OH) · 2H2O
2 photos of Phosphofibrite associated with ZinclipscombiteZnFe3+2(PO4)2(OH)2
2 photos of Phosphofibrite associated with StrengiteFePO4 · 2H2O
2 photos of Phosphofibrite associated with BariopharmacosideriteBa0.5Fe3+4(AsO4)3(OH)4 · 5H2O
1 photo of Phosphofibrite associated with BerauniteFe3+6(PO4)4O(OH)4 · 6H2O

Related Minerals - Strunz-mindat GroupingHide

8.DJ.05JohnwalkiteK(Mn2+,Fe2+,Fe3+)2(Nb5+,Ta5+)(PO4)2O2 · 2(H2O,OH)Orth. mm2
8.DJ.05OlmsteaditeKFe2+2(Nb5+,Ta5+)(PO4)2O2 · 2H2OOrth. mm2
8.DJ.10GatumbaiteCaAl2(PO4)2(OH)2 · H2OMon. 2/m : P2/m
8.DJ.15CamgasiteCaMg(AsO4)(OH) · 5H2OMon. 2/m : P21/m
8.DJ.20Meurigite-KKFe3+8(PO4)6(OH)7 · 6.5H2OMon. 2/m : B2/b
8.DJ.20Meurigite-NaNaFe3+8(PO4)6(OH)7 · 6.5H2OMon. 2/m : B2/b
8.DJ.25JungiteCa2Zn4Fe3+8(PO4)9(OH)9 · 16H2OOrth. mm2 : Aba2
8.DJ.30WycheproofiteNaAlZr(PO4)2(OH) · H2OTric. 1 : P1
8.DJ.35ErcititeNa2Mn3+2(PO4)2(OH)2 · 4H2OOrth. mmm(2/m2/m2/m) : Cmca
8.DJ.40MrázekiteBi2Cu3(PO4)2O2(OH)2 · H2OMon. 2/m
8.DJ.45AttikaiteCa3Cu2Al2(AsO4)4(OH)4 · 2H2OOrth. mmm(2/m2/m2/m) : Pban
8.DJ.50MengeiteBa(Mg,Mn2+)Mn3+4(PO4)4(OH)4 · 4H2OTric. 1 : P1

Other InformationHide

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 PhosphofibriteHide

References for PhosphofibriteHide

Localities for PhosphofibriteHide

Showing 6 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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Locality ListHide

- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Germany (TL)
 
  • Baden-Württemberg
    • Freiburg Region
      • Ortenaukreis
        • Oberwolfach
Walenta et al. (1984) +2 other references
Spain
 
  • Extremadura
    • Badajoz
      • Oliva de Mérida
Calvo Rebollar (2015)
USA
 
  • Nevada
    • Eureka County
      • Carlin Trend
        • Maggie Creek Mining Subdistrict
Newmont Mining Corporation
      • Lynn Mining District
Jensen et al. (1995)
    • Humboldt County
      • Iron Point Mining District
        • Valmy
Castor et al. (2004)
  • New Mexico
    • Grant County
Northrop et al. (1996)
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