Fluellite
A valid IMA mineral species - grandfathered
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About Fluellite
Formula:
Al2(PO4)F2(OH) · 7H2O
Colour:
Colourless, white, yellow
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.139 - 2.17
Crystal System:
Orthorhombic
Name:
In allusion to the composition, being a fluate of alumine (French).
This page provides mineralogical data about Fluellite.
Unique Identifiers
Mindat ID:
1565
Long-form identifier:
mindat:1:1:1565:9
IMA Classification of Fluellite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Al2(PO4)F2(OH)·7H2O
First published:
1824
Type description reference:
Classification of Fluellite
8.DE.10
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
E : With only medium-sized cations, (OH, etc.):RO4 = 3:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
E : With only medium-sized cations, (OH, etc.):RO4 = 3:1
42.6.9.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
22.1.14
22 : Phosphates, Arsenates or Vanadates with other Anions
1 : Phosphates, arsenates or vanadates with fluoride
22 : Phosphates, Arsenates or Vanadates with other Anions
1 : Phosphates, arsenates or vanadates with fluoride
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 for Standard |
|---|---|---|
| Fll | 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 Fluellite
Vitreous
Transparency:
Transparent
Colour:
Colourless, white, yellow
Streak:
White
Hardness:
3 on Mohs scale
Cleavage:
Poor/Indistinct
On {010} and {111}.
On {010} and {111}.
Density:
2.139 - 2.17 g/cm3 (Measured) 2.29 g/cm3 (Calculated)
Optical Data of Fluellite
Type:
Biaxial (+)
RI values:
nα = 1.473 - 1.49 nβ = 1.49 - 1.496 nγ = 1.506 - 1.511
Max. Birefringence:
δ = 0.021 - 0.033
Based on recorded range of RI values above.
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.
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:
Moderate (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
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 (82°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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 (82°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
none
Chemistry of Fluellite
Mindat Formula:
Al2(PO4)F2(OH) · 7H2O
Element Weights:
Crystallography of Fluellite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Fddd
Cell Parameters:
a = 11.22 Å, b = 21.15 Å, c = 8.54 Å
Ratio:
a:b:c = 0.53 : 1 : 0.404
Unit Cell V:
2,026.57 ų (Calculated from Unit Cell)
Morphology:
Crystals dipyramidal {111}, often modified by {010}.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000151 | Fluellite | Guy B B, Jeffrey G A (1966) The crystal structure of fluellite, Al2PO4F2(OH).7H2O American Mineralogist 51 1579-1592 |  | 1966 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.48 Å | (100) |
| 3.24 Å | (70) |
| 3.09 Å | (60) |
| 2.667 Å | (60) |
| 4.96 Å | (50) |
| 2.868 Å | (50) |
| 2.763 Å | (50) |
Comments:
Stenna Gwynn mine, Cornwall, England, ICDD 19-38.
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] |
Geological Setting:
In pegmatites
Type Occurrence of Fluellite
General Appearance of Type Material:
Transparent acute rhombic octahedrons
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, C1028.
Associated Minerals at Type Locality:
Synonyms of Fluellite
Other Language Names for Fluellite
Dutch:Fluelliet
French:Fluate of Alumine
German:Fluellit
Kreuzbergit
Kreuzbergit
Russian:Флюеллит
Simplified Chinese:氟磷铝石
Spanish:Fluellita
Kreuzbergita
Kreuzbergita
Traditional Chinese:氟磷鋁石
Common Associates
Associations Based on Photo Data:
| 47 photos of Fluellite associated with Metavariscite | AlPO4 · 2H2O |
| 41 photos of Fluellite associated with Wavellite | Al3(PO4)2(OH)3 · 5H2O |
| 33 photos of Fluellite associated with Crandallite | CaAl3(PO4)(PO3OH)(OH)6 |
| 22 photos of Fluellite associated with Variscite | AlPO4 · 2H2O |
| 21 photos of Fluellite associated with Quartz | SiO2 |
| 20 photos of Fluellite associated with Nevadaite | (Cu2+,Al,V3+)6Al8(PO4)8F8(OH)2 · 22H2O |
| 12 photos of Fluellite associated with Hewettite | CaV6O16 · 9H2O |
| 11 photos of Fluellite associated with Minyulite | KAl2(PO4)2F · 4H2O |
| 10 photos of Fluellite associated with Aldermanite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2(OH,F)6] · H2O |
| 6 photos of Fluellite associated with Opal | SiO2 · nH2O |
Related Minerals - Strunz-mindat Grouping
| 8.DE. | Arsenoveszelyite | Cu2Zn(AsO4)(OH)3 · 2H2O |
| 8.DE. | Kipushite | (Cu,Zn)5Zn(PO4)2(OH)6 · H2O |
| 8.DE. | Goldhillite | Cu5Zn(AsO4)2(OH)6 · H2O |
| 8.DE.05 | Senegalite | Al2(PO4)(OH)(OH)2 · H2O |
| 8.DE.15 | Bulachite | Al6(AsO4)3(OH)9(H2O)4 · 2H2O |
| 8.DE.20 | Zapatalite | Cu3Al4(PO4)3(OH)9 · 4H2O |
| 8.DE.25 | Ceruleite | Cu2Al7(AsO4)4(OH)13 · 11.5H2O |
| 8.DE.30 | Veszelyite | (Cu,Zn)2Zn(PO4)(OH)3 · 2H2O |
| 8.DE.35 | Philipsburgite | Cu5Zn(AsO4)(PO4)(OH)6 · H2O |
| 8.DE.40 | Juanitaite | (Cu,Ca,Fe)10Bi(AsO4)4(OH)11 · 2H2O |
| 8.DE.45 | Iangreyite | Ca2Al7(PO4)2(PO3OH)2(OH,F)15 · 8H2O |
Fluorescence of Fluellite
May fluoresce creamy white under SW, MW and LW (Harold Moritz comm., 2022).
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 Fluellite
mindat.org URL:
https://www.mindat.org/min-1565.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Fluellite
Reference List:
Laubmann, H.; Steinmetz, H. (1915) Phosphatführende Pegmatite des Oberpfälzer und Bayerischen Waldes. Zeitschrift für Kristallographie, Mineralogie und Petrographie, 55 (1-6). 523-586 doi:10.1524/zkri.1915.55.1.523p.551 - (as Kreuzbergite)
Guy, Brian B., Jeffrey, G. A. (1966) The crystal structure of fluellite, Al2PO4F2(OH)·7H2O. American Mineralogist, 51 (11-12) 1579-1592
Guy, Brian B., Jeffrey, G. A., Tassel, R. Van (1967) The crystal structure of fluellite: A correction. American Mineralogist, 52 (9-10) 1576
Čejka, Jiří, Sejkora, Jiří, Macek, Ivo, Frost, Ray L., López, Andrés, Scholz, Ricardo, Xi, Yunfei (2014) A vibrational spectroscopic study of a hydrated hydroxy-phosphate mineral fluellite, Al2(PO4)F2(OH)·7H2O. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 126. 157-163 doi:10.1016/j.saa.2014.01.116
Localities for Fluellite
Showing 53 localities.
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.
Argentina | |
| Minerals acquired from Mr. Nelson ... +1 other reference |
| Dina (1993) |
| Demartin et al. (1997) | |
Australia | |
| Murray (1973) +1 other reference |
| Segnit et al. (1981) +2 other references |
| Francis et al. (self published) | |
| - (1981) +2 other references |
| - (1981) |
| Francis et al. (self published) |
| Peter Elliott |
| Henderson (1981) |
| |
| Birch et al. (1993) | |
| Museum Victoria Mineralogy Collection +1 other reference |
Belgium | |
| Van Tassel (1959) +1 other reference |
| Jockin (en collaboration avec l'université de Liège) +4 other references | |
Brazil | |
| Witzke et al. (2000) |
China | |
| Shen (n.d.) |
| Jordi Fabre | |
| Wang et al. (2026) |
Czech Republic | |
| Černý et al. (Weisser Stein) |
| Petr Pauliš (2000) +1 other reference |
France | |
| Kolitsch et al. (2009) |
| Meisser et al. (2008) +1 other reference |
Germany | |
| Fehr et al. (1985) |
| Palache et al. (1951) +1 other reference |
| Palache et al. (1951) +2 other references |
| Thalheim et al. (2006) |
Italy | |
| Menchetti et al. (1981) +1 other reference |
Kyrgyzstan | |
| Karpenko et al. (2009) |
Morocco | |
| Favreau (2012) |
Russia | |
| Rychagov et al. (2017, November) |
| Gamyanin et al. (2014) |
| Gongalsky et al. (2019) |
Spain | |
| Calvo Rebollar et al. (2024) |
| Calvo et al. (2003) +1 other reference |
Sweden | |
| Bjällerud (1989) +1 other reference |
UK (TL) | |
| Rudler (1905) +3 other references |
| Kingsbury (1959) +1 other reference |
USA | |
| Kampf et al. (2013) |
| Newmont Mining Corporation |
| Jensen et al. (1995) |
| Barrick Gold Corporation | |
| Dr. William S. Wise presentation to ... |
| Jensen et al. (2001) +1 other reference |
| - (1977) |
| Peacor et al. (1984) |
| O'Neill (2014) |
| Bullock (1981) |
| Bullock (1981) |
| Petersen et al. (1993) |
| Lovering et al. (1960) |
| Kearns et al. (2000) |
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Richelle, Visé, Liège, Wallonia, Belgium