Chemistry:Tungstite

From HandWiki
Short description: Hydroxide mineral
Tungstite
Tungstite on ferberite.jpg
Bright yellow tungstite on ferberite
General
CategoryMineral
Formula
(repeating unit)
WO3·H2O
Strunz classification4.FJ.10
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPmnb
Identification
Formula mass249.86 g/mol
ColorYellow, yellowish green/orange
Crystal habitEarthy, pulverulent
CleavagePerfect along [001], imperfect along [110]
Mohs scale hardness2.5
|re|er}}Resinous, pearly
StreakYellow
DiaphaneityTransparent
Specific gravity5.517
Optical propertiesBiaxial (-)
Refractive indexnα = 2.090, nβ = 2.240, nγ = 2.260
Birefringenceδ = 0.170
Dispersionr < v (strong)

Tungstite is a hydrous tungsten oxide mineral with formula: WO3·H2O. It is a secondary mineral formed by the weathering of other tungsten containing minerals. It crystallizes in the orthorhombic system in translucent yellow to yellow green masses. It is clay-like with Mohs hardness of 2.5 and a specific gravity of 5.5.

It was first described in 1868 for an occurrence near Trumbull, Connecticut at the Hubbard Tungsten Mine at Long Hill.

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode2021MinM...85..291W.