Wulfenite

Wulfenite
Wulfenite from Red Cloud mine, Arizona
General
CategoryMolybdate mineral
Formula
(repeating unit)
PbMoO4
IMA symbolWul[1]
Strunz classification7.GA.05
Crystal systemTetragonal
Crystal classDipyramidal (4/m)
H-M symbol: (4/m)
Space groupI41/a
Unit cella = 5.433, c = 12.110 [Å]; Z = 4
Identification
ColorOrange-yellow, yellow, honey-yellow, reddish-orange, rarely colorless, grey, brown, olive-green and even black
Crystal habitThin tabular to pyramidal
TwinningTwins on the [001] common
CleavageOn {011}, distinct; on {001}, {013}, indistinct
FractureIrregular to sub-conchoidal
TenacityBrittle
Mohs scale hardness3
LusterAdamantine, resinous
StreakWhite
DiaphaneityTransparent to opaque
Specific gravity6.5–7.0
Optical propertiesUniaxial (−), may be anomalously biaxial
Refractive indexnω = 2.405 nε = 2.283
Birefringenceδ = 0.122
PleochroismWeak; orange and yellow
Ultraviolet fluorescenceNone
Other characteristicsSpecimens may be piezoelectric
References[2][3][4]

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".

It crystallizes in the tetragonal system, often occurring as stubby, pyramidal or tabular crystals. It also occurs as earthy, granular masses. It is found in many localities, associated with lead ores as a secondary mineral associated with the oxidized zone of lead deposits. It is also a secondary ore of molybdenum, and is sought by collectors.

  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.
  2. ^ "Wulfenite: Mineral information, data and localities".
  3. ^ "Handbook of Mineralogy" (PDF).
  4. ^ "Wulfenite Mineral Data". www.webmineral.com.