Laurionite
(repeating unit)PbCl(OH) IMA symbol Lri[1] Strunz classification 3.DC.05 Crystal system Orthorhombic Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Space group Pnma Unit cell a = 7.111, b = 9.6987
c = 4.0203 [Å]; Z = 4 Identification Color Colorless, white Crystal habit Elongated tabular prismatic crystals Cleavage Distinct on {101} Tenacity Flexible Mohs scale hardness 3–3.5 Luster Adamantine, pearly Streak White Diaphaneity Transparent Specific gravity 6.241 Optical properties Biaxial (−) Refractive index nα = 2.077 nβ = 2.116 nγ = 2.158 Birefringence δ = 0.081 2V angle Measured: 70° Solubility Sleight in cold water References [2][3][4][5]
H-M symbol: (2/m 2/m 2/m)
c = 4.0203 [Å]; Z = 4
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]
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