Vanuralite
A valid IMA mineral species
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About Vanuralite
Formula:
Al(UO2)2(V2O8)(OH) · 11H2O
The formula of vanuralite and related minerals is commonly mistakenly written as to be containing VO4 groups. Since the structure does not contain any of them, but V2O8 dimers (pairs of edge-sharing VO5 tetragonal pyramids), the formula has to be written as Al[(UO2)2V2O8(OH)].11H2O. The real H2O content can be significantly lower (8.5H2O according to structure determination of Plášil, 2017).
Colour:
Citron-yellow, canary-yellow, pale yellow
Hardness:
2
Specific Gravity:
3.62
Crystal System:
Monoclinic
Member of:
Name:
The name reflects its composition: VANadium, URanium and ALuminium.
This page provides mineralogical data about Vanuralite.
Unique Identifiers
Mindat ID:
4152
Long-form identifier:
mindat:1:1:4152:8
Classification of Vanuralite
Francevillite sheet topology
The sheet topology found in minerals of the carnotite group.
IMA Classification of Vanuralite
Approved
IMA Formula:
Al(U6+O2)2(V5+O4)2(OH)·8.5H2O
First published:
1963
Type description reference:
4.HB.20
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
B : Uranyl Sorovanodates
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
B : Uranyl Sorovanodates
Dana 7th ed.:
42.11.15.1
42.11.13.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
21.4.12
21 : Vanadates (and vanadates with arsenate or phosphate)
4 : Vanadates of U, Mn, Fe or Ni
21 : Vanadates (and vanadates with arsenate or phosphate)
4 : Vanadates of U, Mn, Fe or Ni
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 |
|---|---|---|
| Vnr | 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 Vanuralite
Transparency:
Translucent
Colour:
Citron-yellow, canary-yellow, pale yellow
Hardness:
2 on Mohs scale
Cleavage:
Perfect
On {001}
On {001}
Density:
3.62 g/cm3 (Measured) 3.16 g/cm3 (Calculated)
Optical Data of Vanuralite
Type:
Biaxial (-)
RI values:
nα = 1.65 nβ = 1.85 nγ = 1.90
2V:
Measured: 44° , Calculated: 46°
Max. Birefringence:
δ = 0.250
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:
Very High (positive)
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.
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.
Dispersion:
relatively strong
Pleochroism:
Strong
Comments:
X = colorless; Y = Z = yellow.
Chemistry of Vanuralite
Mindat Formula:
Al(UO2)2(V2O8)(OH) · 11H2O
The formula of vanuralite and related minerals is commonly mistakenly written as to be containing VO4 groups. Since the structure does not contain any of them, but V2O8 dimers (pairs of edge-sharing VO5 tetragonal pyramids), the formula has to be written as Al[(UO2)2V2O8(OH)].11H2O. The real H2O content can be significantly lower (8.5H2O according to structure determination of Plášil, 2017).
The formula of vanuralite and related minerals is commonly mistakenly written as to be containing VO4 groups. Since the structure does not contain any of them, but V2O8 dimers (pairs of edge-sharing VO5 tetragonal pyramids), the formula has to be written as Al[(UO2)2V2O8(OH)].11H2O. The real H2O content can be significantly lower (8.5H2O according to structure determination of Plášil, 2017).
Element Weights:
Crystallography of Vanuralite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 10.55(3) Å, b = 8.44(3) Å, c = 24.52(5) Å
β = 103.0(3)°
β = 103.0(3)°
Ratio:
a:b:c = 1.25 : 1 : 2.905
Unit Cell V:
2,127.35 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Elongated on [010]. Forms include prominent {100} and {001}, with smaller {011}, {110}, {111}, {111}, {113}.
Twinning:
Composition plane {001}
Comment:
Space Group: A21/a.
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.96 Å | (90) |
| 5.00 Å | (80) |
| 3.326 Å | (30) |
| 2.679 Å | (25) |
| 2.490 Å | (18) |
Comments:
11.98 (FFF), 5.98 (FF), 3.975 (Fd), 3.231 (F), 3.180 (F), 5.14 (mF), 6.53 (mf)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Type Occurrence of Vanuralite
General Appearance of Type Material:
Yellow plates
Place of Conservation of Type Material:
National School of Mines, Paris, France.
The Natural History Museum, London, England.
The Natural History Museum, London, England.
Geological Setting of Type Material:
Supergene deposit
Associated Minerals at Type Locality:
Synonyms of Vanuralite
Other Language Names for Vanuralite
Relationship of Vanuralite to other Species
Member of:
Other Members of Carnotite Group:
| Carnotite | K2(UO2)2(VO4)2 · 3H2O | Mon. 2/m : P21/b |
| Margaritasite | (Cs,K,H3O)2(UO2)2(VO4)2 · H2O | Mon. 2/m : P21/b |
| Metatyuyamunite | Ca(UO2)2(VO4)2 · 3H2O | Orth. mmm(2/m2/m2/m) |
| Metavanuralite | Al(UO2)2(VO4)2(OH) · 8H2O | Tric. |
| Sengierite | Cu2(UO2)2(VO4)2 · 6H2O | Mon. 2/m : P21/b |
| Strelkinite | Na2(UO2)2(VO4)2 · 6H2O | Orth. |
| Tyuyamunite | Ca(UO2)2(VO4)2 · 5-8H2O | Orth. mmm(2/m2/m2/m) : Pnna |
Common Associates
Associations Based on Photo Data:
| 5 photos of Vanuralite associated with Francevillite | Ba(UO2)2(VO4)2 · 5H2O |
| 4 photos of Vanuralite associated with Mounanaite | PbFe3+2(VO4)2(OH)2 |
| 2 photos of Vanuralite associated with Chervetite | Pb2(V2O7) |
| 1 photo of Vanuralite associated with Curienite | Pb(UO2)2(VO4)2 · 5H2O |
| 1 photo of Vanuralite associated with 'Curienite-Francevillite Series' |
Related Minerals - Strunz-mindat Grouping
| 4.HB.X | Spanoite | Tl2[(UO2)2(V2O8)] |
| 4.HB.05 | Margaritasite | (Cs,K,H3O)2(UO2)2(VO4)2 · H2O |
| 4.HB.05 | Carnotite | K2(UO2)2(VO4)2 · 3H2O |
| 4.HB.10 | Sengierite | Cu2(UO2)2(VO4)2 · 6H2O |
| 4.HB.15 | Francevillite | Ba(UO2)2(VO4)2 · 5H2O |
| 4.HB.15 | Fritzscheite | Mn2+(UO2)2(VO4,PO4)2 · 4H2O |
| 4.HB.15 | Curienite | Pb(UO2)2(VO4)2 · 5H2O |
| 4.HB.15 | Finchite | Sr(UO2)2(V2O8) · 5H2O |
| 4.HB.20 | Metavanuralite | Al(UO2)2(VO4)2(OH) · 8H2O |
| 4.HB.25 | Metatyuyamunite | Ca(UO2)2(VO4)2 · 3H2O |
| 4.HB.25 | Tyuyamunite | Ca(UO2)2(VO4)2 · 5-8H2O |
| 4.HB.30 | Strelkinite | Na2(UO2)2(VO4)2 · 6H2O |
| 4.HB.35 | Uvanite | U6+2V5+6O21 · 15H2O (?) |
| 4.HB.40 | Rauvite | Ca(UO2)2(V10O28) · 16H2O |
| 4.HB.45 | Vandermeerscheite | K2[(UO2)2V2O8] · 2H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 47.0371% | 11,759,275 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 0.0000% | 0 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
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 Vanuralite
mindat.org URL:
https://www.mindat.org/min-4152.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Vanuralite
Localities for Vanuralite
Showing 6 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.
African Plate | |
| Badahmaoui et al. (2020) |
Gabon (TL) | |
| Branche et al. (1963) +2 other references |
Russia | |
| Eremin et al. (2023) |
Spain | |
| Castillo-Oliver et al. (2019) |
| Calvo Rebollar (2009) |
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Mounana Mine, Mounana, Léboumbi-Leyou Department, Haut-Ogooué Province, Gabon