Uranotungstite
A valid IMA mineral species
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About Uranotungstite
Formula:
(Ba0.35Pb0.27)Σ0.62[(U6+O2)2(W6+0.98Fe3+0.26◻0.75)O4.7(OH)2.5(H2O)1.75](H2O)1.67
Formular originally assumed to be (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4 · 12H2O (Walenta, 1985).
Colour:
Yellow, orange, brown, blackish
Lustre:
Pearly, Dull
Hardness:
2
Specific Gravity:
>4.03
Crystal System:
Monoclinic
Name:
The name reflects its composition: Uranium and Tungsten.
Originally assumed to be orthorhombic and having the chemical formula (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4 · 12H2O (Walenta, 1985). A restudy of type material and other material, including a crystal-structure determination, showed the mineral to be in fact monoclinic, with space group P21/m, and to have a fairly different formula (Steciuk et al., 2022).
Unique combination of elements (status: 2023); the first mineral with species-defining Ba and W (compare ronpetersonite).
Compare the closely related, but Pb-dominant wolfsriedite.
Unique combination of elements (status: 2023); the first mineral with species-defining Ba and W (compare ronpetersonite).
Compare the closely related, but Pb-dominant wolfsriedite.
Unique Identifiers
Mindat ID:
4115
Long-form identifier:
mindat:1:1:4115:3
IMA Classification of Uranotungstite
Approved
IMA Formula:
Ba(U6+O2)2W6+2O8(OH)2·H2O
Approval year:
1984
First published:
1985
Classification of Uranotungstite
7.HB.25
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
H : Uranium and uranyl molybdates and wolframates
B : With U6+
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
H : Uranium and uranyl molybdates and wolframates
B : With U6+
49.3.5.1
49 : HYDRATED MOLYBDATES AND TUNGSTATES
3 : Hydrated Molybdates and Tungstates Containing Hydroxyl or Halogen
49 : HYDRATED MOLYBDATES AND TUNGSTATES
3 : Hydrated Molybdates and Tungstates Containing Hydroxyl or Halogen
27.4.12
27 : Sulphites, Chromates, Molybdates and Tungstates
4 : Tungstates
27 : Sulphites, Chromates, Molybdates and Tungstates
4 : Tungstates
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 |
|---|---|---|
| Utgs | 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 Uranotungstite
Pearly, Dull
Transparency:
Translucent
Colour:
Yellow, orange, brown, blackish
Streak:
Yellow
Hardness:
2 on Mohs scale
Cleavage:
Perfect
{010}
{010}
Fracture:
Irregular/Uneven
Density:
>4.03 g/cm3 (Measured) 4.27 g/cm3 (Calculated)
Optical Data of Uranotungstite
Type:
Biaxial (-)
RI values:
nα = 1.682(5) nβ = 1.845(5) nγ = 1.855(5)
2V:
Measured: 42° , Calculated: 24°
Max. Birefringence:
δ = 0.173
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:
r > v moderate
Pleochroism:
Visible
Comments:
X = nearly colorless, Y = Z = yellow
Comments:
X = b
Chemistry of Uranotungstite
Mindat Formula:
(Ba0.35Pb0.27)Σ0.62[(U6+O2)2(W6+0.98Fe3+0.26◻0.75)O4.7(OH)2.5(H2O)1.75](H2O)1.67
Formular originally assumed to be (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4 · 12H2O (Walenta, 1985).
Formular originally assumed to be (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4 · 12H2O (Walenta, 1985).
Crystallography of Uranotungstite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Cell Parameters:
a = 6.318(5) Å, b = 7.388(9) Å, c = 13.71(4) Å
β = 99.04(13)°
β = 99.04(13)°
Ratio:
a:b:c = 0.855 : 1 : 1.856
Unit Cell V:
632.00 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Tabular, lath-shaped (pseudo-orthorhombic).
Twinning:
Pervasive, parallel to the platey face (Kolitsch and Plášil, unpublished data).
Comment:
Originally assumed to be orthorhombic, with a = 9.22, b = 13.81, c = 7.17 Å (Walenta, 1985).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.96 Å | (10) |
| 4.60 Å | (6) |
| 3.46 Å | (5) |
| 3.21 Å | (7) |
| 3.01 Å | (3) |
| 2.77 Å | (4) |
| 1.970 Å | (4) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Type Occurrence of Uranotungstite
Co-Type Localities:
General Appearance of Type Material:
Spherulitic aggregates up to 0.3 mm in diameter.
Place of Conservation of Type Material:
University of Stuttgart, Stuttgart, Germany.
Associated Minerals at Type Locality:
Synonyms of Uranotungstite
Other Language Names for Uranotungstite
Common Associates
Associations Based on Photo Data:
| 4 photos of Uranotungstite associated with Zeunerite | Cu(UO2)2(AsO4)2 · 12H2O |
| 3 photos of Uranotungstite associated with Metatorbernite | Cu(UO2)2(PO4)2 · 8H2O |
| 2 photos of Uranotungstite associated with Tyuyamunite | Ca(UO2)2(VO4)2 · 5-8H2O |
| 2 photos of Uranotungstite associated with Nováčekite | Mg(UO2)2(AsO4)2 · 10H2O |
| 2 photos of Uranotungstite associated with Gearksutite | Ca[Al(F,OH)5(H2O)] |
| 1 photo of Uranotungstite associated with Torbernite | Cu(UO2)2(PO4)2 · 12H2O |
| 1 photo of Uranotungstite associated with Fluorite | CaF2 |
Related Minerals - Strunz-mindat Grouping
| 7.HB.15 | Calcurmolite | Ca[(UO2)3(MoO4)2(OH)4](H2O)~5.0 |
| 7.HB.20 | Tengchongite | Ca(UO2)6(MoO4OH)2O2(OH)4 · 9H2O |
| 7.HB.25 | Wolfsriedite | Pb[(UO2)2(W6+Fe3+)O7(OH)](H2O)3 |
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 Uranotungstite
mindat.org URL:
https://www.mindat.org/min-4115.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Uranotungstite
Reference List:
Walenta, K. (1985) Uranotungstit, ein neues sekundäres Uranmineral aus dem Schwarzwald. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 34 (1). 25-34 doi:10.1007/bf01082455
Localities for Uranotungstite
Showing 8 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.
France | |
| Cuchet et al. (2000) |
| Favreau et al. (2024) |
| Georges FAVREAU collection & EDX ... +1 other reference | |
Germany (TL) | |
| Walenta (1985) +2 other references |
| Walenta (1985) +1 other reference |
Namibia | |
| Schnaitmann et al. (2007) |
| von Bezing (2007) | |
Russia | |
| Alekseev et al. (2015) |
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Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany