Hydrotungstite
A valid IMA mineral species - grandfathered
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About Hydrotungstite
Formula:
WO3 · 2H2O
Colour:
Dark green, becoming yellowish on exposure to air
Lustre:
Vitreous, Dull
Hardness:
2
Specific Gravity:
4.60
Crystal System:
Monoclinic
Dimorph of:
Hydrotungstite is unstable and dehydrates to tungstite, so most specimens in systematic species collections are no longer hydrotungstite.
A hydrated counterpart of liguowuite.
A hydrated counterpart of liguowuite.
Unique Identifiers
Mindat ID:
1988
Long-form identifier:
mindat:1:1:1988:6
Similar Names
| Yttrotungstite-(Ce) | A valid IMA mineral species | CeW2O7(OH) · H2O |
| Yttrotungstite-(Nd) | A valid IMA mineral species | NdW2O7(OH) · H2O |
| Yttrotungstite-(Y) | A valid IMA mineral species - grandfathered | YW2O7(OH) · H2O |
IMA Classification of Hydrotungstite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
W6+O2(OH)2·H2O
Classification of Hydrotungstite
4.FJ.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
J : Hydroxides with H2O +- (OH); corner-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
J : Hydroxides with H2O +- (OH); corner-sharing octahedra
49.1.1.1
49 : HYDRATED MOLYBDATES AND TUNGSTATES
1 : Acid Hydrated Molybdates and Tungstates
49 : HYDRATED MOLYBDATES AND TUNGSTATES
1 : Acid Hydrated Molybdates and Tungstates
7.15.6
7 : Oxides and Hydroxides
15 : Oxides of Mo and W
7 : Oxides and Hydroxides
15 : Oxides of Mo and W
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 |
|---|---|---|
| Htgs | 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 Hydrotungstite
Vitreous, Dull
Transparency:
Translucent
Colour:
Dark green, becoming yellowish on exposure to air
Hardness:
2 on Mohs scale
Cleavage:
Imperfect/Fair
{010}, imperfect
{010}, imperfect
Density:
4.60 g/cm3 (Measured) 4.66 g/cm3 (Calculated)
Optical Data of Hydrotungstite
Type:
Biaxial (-)
RI values:
nα = 1.70(2) nβ = 1.95(2) nγ = 2.04(2)
2V:
Measured: 52° , Calculated: 54°
Max. Birefringence:
δ = 0.340
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
Dispersion:
relatively strong: r < v
Pleochroism:
Visible
Comments:
X = colorless; Y = yellow-green; Z = dark green.
Chemistry of Hydrotungstite
Mindat Formula:
WO3 · 2H2O
Elements listed:
Crystallography of Hydrotungstite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/m
Setting:
P2/m
Cell Parameters:
a = 7.379(5) Å, b = 6.901(5) Å, c = 3.748(5) Å
β = 90.33(12)°
β = 90.33(12)°
Ratio:
a:b:c = 1.069 : 1 : 0.543
Unit Cell V:
190.85 ų (Calculated from Unit Cell)
Z:
2
Twinning:
Polysynthetic, may be grid-like On {210}
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.95 Å | (vvs) |
| 3.73 Å | (s) |
| 3.46 Å | (ms) |
| 3.27 Å | (vs) |
| 2.63 Å | (m) |
| 2.54 Å | (m) |
| 1.96 Å | (ms) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Hydrotungstite
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, 98896; National Museum of Natural History, Washington, D.C., USA, 104901
Associated Minerals at Type Locality:
Synonyms of Hydrotungstite
Other Language Names for Hydrotungstite
Common Associates
Associations Based on Photo Data:
| 27 photos of Hydrotungstite associated with Ferberite | FeWO4 |
| 19 photos of Hydrotungstite associated with Tungstite | WO3 · H2O |
| 8 photos of Hydrotungstite associated with Quartz | SiO2 |
| 6 photos of Hydrotungstite associated with Hübnerite | MnWO4 |
| 1 photo of Hydrotungstite associated with Scheelite | Ca(WO4) |
| 1 photo of Hydrotungstite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 1 photo of Hydrotungstite associated with Fluorite | CaF2 |
| 1 photo of Hydrotungstite associated with Hydrokenoelsmoreite | ◻2W2O6(H2O) |
| 1 photo of Hydrotungstite associated with Cuprotungstite | Cu2(WO4)(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 4.FJ. | Raydemarkite | MoO3 · H2O |
| 4.FJ.05 | Sidwillite | MoO3 · 2H2O |
| 4.FJ.05 | Meymacite | WO3 · 2H2O |
| 4.FJ.10 | Tungstite | WO3 · H2O |
| 4.FJ.15 | Ilsemannite | Mo3O8 · nH2O |
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 Hydrotungstite
mindat.org URL:
https://www.mindat.org/min-1988.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 Hydrotungstite
Localities for Hydrotungstite
Showing 27 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.
Austria | |
| Exel (1993) |
Bolivia | |
| RAMAN confirmation by Joy Desor |
| Kempff et al. (La Paz, 2009) |
| Kerr et al. (1944) | |
Bulgaria | |
| Tarassov et al. (2018) |
Canada | |
| Chatterjee (1977) |
France | |
| Gourault et al. (2021) |
| Ansermet et al. (2010) |
| Queneau (n.d.) |
Germany | |
| Walenta (1992) |
Japan | |
| Matsuo et al (1981) |
Norway | |
| Folvik (2008) +1 other reference |
Peru | |
| Hyršl (2011) |
| Hyršl (2011) | |
Portugal | |
| Bussink (1984) | |
Romania | |
| Szakáll (2002) |
Russia | |
| Silyanov et al. (2021) |
| Kasatkin et al. (2014) |
| Eremin et al. (2023) |
Rwanda | |
| Andreas Schloth collection |
| Roy Kristiansen |
Slovakia | |
| Števko M. et al. (Slovenská republika) |
| Koděra et al. (2025) | |
| Števko M. et al. (Slovenská republika) | |
Turkey | |
| Powell et al. (2021) |
USA | |
| Jeremy Zolan |
| Castor et al. (2004) |
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Ferimolybditová vein, Ochtiná, Rožňava District, Košice Region, Slovakia