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Hydrotungstite

Big Photo

Lutsiro, Sebeya river, Kabaya District, Rwanda
© R.Kristiansen

Formula:
WO
 
3
·2H
 
2
O
System:MonoclinicColour: Dark green, ...
Hardness:2


Hydrotungstite is unstable and dehydrates to tungstite, so most specimens in systematic species collections are no longer hydrotungstite.

Classification of Hydrotungstite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/E.02-30
Nickel-Strunz 10th (pending) edition ID: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
Dana 8th edition ID:49.1.1.1

49 : HYDRATED MOLYBDATES AND TUNGSTATES
1 : Acid Hydrated Molybdates and Tungstates
Hey's CIM Ref.:7.15.6

7 : Oxides and Hydroxides
15 : Oxides of Mo and W
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Type Occurrence of Hydrotungstite

Type Locality:San Antonio de Calacalani mine, Cercado Province, Oruro Department, Bolivia
Year of Discovery:1940

Physical Properties of Hydrotungstite

Colour: Dark green, becoming yellowish on exposure to air
Hardness (Mohs):2

Crystallography of Hydrotungstite

Crystal System:Monoclinic
Cell Parameters:a = 7.45Å, b = 6.92Å, c = 3.72Å
β = 90.5°
Ratio:a:b:c = 1.077 : 1 : 0.538
Unit Cell Volume:V 191.77 ų (Calculated from Unit Cell)
Twinning:Polysynthetic, may be grid-like
X-Ray Powder Diffraction:
d-spacingIntensity
6.95 (vvs)
3.73 (s)
3.46 (ms)
3.27 (vs)
2.63 (m)
2.54 (m)

Optical Data of Hydrotungstite

Type:Biaxial (-)
RI values: nα = 1.700 nβ = 1.950 nγ = 2.040
2V:Measured: 52° , Calculated: 54°
Maximum Birefringence:δ = 0.340

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Very High
Dispersion:relatively strong

Chemical Properties of Hydrotungstite

Formula:
WO
 
3
·2H
 
2
O
Essential elements:H, O, W
All elements listed in formula:H, O, W

Relationship of Hydrotungstite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
4.FJ.05Meymacite
WO
 
3
·2H
 
2
O
4.FJ.05Sidwillite
MoO
 
3
·2H
 
2
O
4.FJ.10Tungstite
WO
 
3
·H
 
2
O
4.FJ.15Ilsemannite
Mo
 
3
O
 
8
·nH
 
2
O
4.FJ.20Parabariomicrolite
BaTa
 
4
O
 
10
(OH)
 
2
·2H
 
2
O
Related Minerals - Hey's Index Grouping:

- +
7.15.1Tugarinovite
MoO
 
2
7.15.2Molybdite
MoO
 
3
7.15.3Sidwillite
MoO
 
3
·2H
 
2
O
7.15.4Ilsemannite
Mo
 
3
O
 
8
·nH
 
2
O
7.15.5Tungstite
WO
 
3
·H
 
2
O
7.15.7Meymacite
WO
 
3
·2H
 
2
O
7.15.8Alumotungstite
(W,Al)(O,OH)
 
3
7.15.9Jixianite
Pb(W,Fe
3+
 
)
 
2
(O,OH)
 
7

Other Names for Hydrotungstite

Synonyms:
Hydrotungstenite
Other Languages:
German:Hydrotungstit
Spanish:Hydrotungstita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Hydrotungstite

Reference List:American Mineralogist: 29: 192-210.

Mineralogical Record (1981): 12: 81-85.

Internet Links for Hydrotungstite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
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  • Hydrotungstite details from Handbook of Mineralogy (PDF)
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    Localities for Hydrotungstite

    Hide Locality List
    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Austria
     
    • Tyrol
      • North Tyrol
        • Ziller valley
          • Tux valley
            • Tux (Lanersbach; Lannersbach)
    		R. Exel: Die Mineralien und Erzlagerstätten Österreichs (1993)
    Bolivia
     
    • Oruro Department
      • Cercado Province
    		Amer. Mineral. (1944) 29, 192–210
    Germany
     
    • Baden-Württemberg
      • Black Forest
        • Wolfach
          • Oberwolfach
            • Rankach valley
    		Walenta, K. (1992): Die Mineralien des Schwarzwaldes. Chr. Weise Verlag, München, 336 pp. (in German)
    Japan
     
    • Honshu Island
      • Kinki Region
        • Kyoto Prefecture
          • Kameoka City
    		Matsuo et al (1981) Kyoto Chigakukaisha, 34, 6-43
    Norway
     
    • Oppland
      • Lunner
        • Grua Mining District
    		Folvik, H. O. (2008): Nytt om mineraler. Tre nye mineraler fra Skjerpemyr, Grua. STEIN 35 (1): 16
    Portugal
     
    • Castelo Branco District
      • Covilhã
        • Panasqueira
    		No reference listed
    Rwanda
     
    • Kabaya District
      • Sebeya river
    		Roy Kristiansen
    USA
     
    • Connecticut
      • Fairfield Co.
        • Trumbull
    		Jeremy Zolan
    • Nevada
      • Churchill Co.
        • Toy District
    		NBMG Spec. Pub. 31 Minerals of Nevada
    Mineral and/or Locality
    Google
     
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