Laurionite

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Laurionite
Laurionite-154998.jpg
Laurionite crystals in a vug from the Laurium district of Greece
General
CategoryHalide minerals
Formula
(repeating unit)
PbCl(OH)
IMA symbolLri[1]
Strunz classification3.DC.05
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma
Unit cella = 7.111, b = 9.6987
c = 4.0203 [Å]; Z = 4
Identification
ColorColorless, white
Crystal habitElongated tabular prismatic crystals
CleavageDistinct on {101}
TenacityFlexible
Mohs scale hardness3 - 3.5
LusterAdamantine, pearly
StreakWhite
DiaphaneityTransparent
Specific gravity6.241
Optical propertiesBiaxial (-)
Refractive indexnα = 2.077 nβ = 2.116 nγ = 2.158
Birefringenceδ = 0.081
2V angleMeasured: 70°
SolubilitySleight in cold water
References[2][3][4][5]

Laurionite (PbCl(OH)) is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group.[2]

It was first described in 1887 for an occurrence in the Laurium District, Attica, Greece, and named after the town Laurium.[2] It occurs as an oxidation product in lead ore deposits, and is also produced on lead-bearing slag by reaction with saline solutions. It occurs associated with paralaurionite, penfieldite, fiedlerite, phosgenite, cerussite and anglesite.[3]

References[edit]

  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. ^ a b c Mindat.org
  3. ^ a b Handbook of Mineralogy
  4. ^ Webmineral data for laurionite
  5. ^ Mineralienatlas