Lead Arseno Chloride
Pb5(AsO4)3Cl
Chemical name
Lead Arseno Chloride
Mineral name
Mimetesite
Chemical formula
Pb5(AsO4)3Cl
Crystal system
hexagonal
Crystal Class
hexagonal-dipyramidal (6/m)
Space Group
P6_3/m
Unit cell
a [Å]:10.211
b [Å]:10.211
c [Å]:7.418
Molecular weight [g/mol]
1488,25
Formula units
Z=2
Frequent crystal surfaces
{10-10}, {0001}, {10-11}, {11-21}, {21-31}
Twinning
rare on {11-22}
Mohs hardness
3.8 - 4
Density [g/cm3]
~7:2
Cleavage
imperfect on [10-11]
Fracture / Tenacity
conchoidal, brittle
Color
pale to bright yellow, yellowish brown, yellow-orange, white, colorless
Streak
white
Transparency
transparent to translucent
Optical character
uniaxial (-)
Refractive Index
nω=2.147; nε=2.128
Birefringence δ
0.019
Pleochroism δ
weak