Tungstite

Tungstite
Bright yellow tungstite on ferberite
General
CategoryMineral
Formula
(repeating unit)
WO3·H2O
IMA symbolTgs[1]
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
LusterResinous, 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.

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.