Platey clear paralaurionite crystals from slag in the Thorikos area, Lavrion, Attica, Greece
General
Category
Halide mineral
Formula (repeating unit)
PbCl(OH)
IMA symbol
Plri[1]
Strunz classification
3.DC.05
Crystal system
Monoclinic
Crystal class
Prismatic (2/m) (same H-M symbol)
Space group
C2/m
Unit cell
a = 10.865(4) Å, b = 4.006(2) Å, c = 7.233(3) Å; β = 117.24(4)°; Z = 4
Identification
Color
Colorless, white, pale greenish, yellowish, yellow-orange, rarely violet
Crystal habit
Elongated tabular crystals
Twinning
Contact twinning on {100}
Cleavage
Perfect on {001}
Tenacity
Flexible, non-elastic
Mohs scale hardness
3
Luster
Subadamantine
Diaphaneity
Transparent to translucent
Specific gravity
6.05–6.15
Optical properties
Biaxial (−)
Refractive index
nα = 2.050 nβ = 2.150 nγ = 2.200
Birefringence
δ = 0.150
Pleochroism
Visible
References
[2][3][4][5]
Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite group.[6] The name is derived from para-, the Greek for "near", and laurionite, because of its polymorphic relationship to it.[4] Bright, yellow tips of thorikosite can form on paralaurionite crystals and paralaurionite may also be intergrown with mendipite.[7][8]
Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite...
crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group. It was first described in 1887...
in Mendipite as Pb3Cl2O2, and in the dimorph minerals laurionite and paralaurionite, which are PbCl(OH) members of the matlockite group. Historically, the...
deposit. Specimens found in Greece were associated with phosgenite and paralaurionite, while the Italian specimens were found in association with cotunnite...