Linarite

Linarite is a somewhat rare, crystalline mineral that is known among mineral collectors for its unusually intense, pure blue color. It is formed by the oxidation of galena and chalcopyrite and other copper sulfides. It is a combined copper lead sulfate hydroxide with formula PbCuSO4(OH)2. Linarite occurs as monoclinic prismatic to tabular crystals and irregular masses. It is easily confused with azurite, but does not react with dilute hydrochloric acid as azurite does. It has a Mohs hardness of 2.5 and a specific gravity of 5.3 - 5.5.

Linarite
General
CategorySulfate minerals
Formula
(repeating unit)		PbCu[(OH)2|SO4]
Strunz classification7.BC.65
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/m
Unit cella = 9.701(2), b = 5.65
c = 4.69 [Å]; β = 102.65°; Z = 2
Identification
ColorDeep azure blue
Crystal habitCrystals elongated and tabular; in crusts and aggregates
TwinningCommon on {100}, also on {001}
CleavagePerfect on {100}, imperfect on {001}
FractureConchoidal
Mohs scale hardness2.5
LusterSub-adamantine, vitreous
StreakPale blue
DiaphaneityTransparent, translucent
Specific gravity5.3 - 5.5
Optical propertiesBiaxial (-)
Refractive indexnα = 1.809 nβ = 1.838 nγ = 1.859
Birefringenceδ = 0.050
PleochroismX = pale blue; Y = blue; Z = Prussian blue
2V angleMeasured: 80°
References[1][2][3]

Linarite was first identified in 1822. It is named after the Linares Plateau, Spain.[1] It occurs in association with brochantite, anglesite, caledonite, leadhillite, cerussite, malachite and hemimorphite.[3]

  • A shallow pocket of crystals of an intense cobalt blue, from Darwin, Darwin District, Inyo County, California, USA
  • Linarite with malachite, Blanchard Mine, Hansonburg District, Socorro County, New Mexico USA (Size: 1.1 x 0.8 x 0.4 cm)
  • Linarite with caledonite, from Baker, El Dorado County, California USA (Size 5.4 x 5.2 x 3.2 cm)
  • Unusual cerussite with a coating ingrained into the surface of microcrystalline malachite and linarite that give it a rich blue-green color
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References
  1. Mindat
  2. Webmineral
  3. Handbook of Mineralogy
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