Botallackite - Encyclopedia
Class : Halides
Subclass : Oxychlorides
Crystal system : Monoclinic
Chemistry : Cu2Cl(OH)3
Rarity : Very rare
Botallackite is an extremely rare copper chloride, a polymorph of atacamite and paratacamite with which it is usually associated. It is a secondary chloride that is formed at the expense of copper minerals subjected to the action of chlorine solutions or sea water. It is also present in certain slags immersed in the sea, and in the weathered part of black smokers ocean bottoms. It is a mineral which owes its name to its site of discovery : Botallack in English Cornwall. Botallackite forms encrustations of tiny fibrous crystals that are pale green to bluish green, rarely blue.
Main photo : Botallackite from Levant Mine, Cornwall, England © Gianfranco Ciccolini
Botallackite in the World
Twinning
No known twin for this mineral species.
Fakes and treatments
No fake inventories for this mineral species.
Hardness : 3
Density : 3.6
Fracture : Irregular
Trace : Blue-green
TP : Translucent to transparent
RI : 1.775 to 1.846
Birefringence : 0.071
Optical character : Biaxial +
Pleochroism : Low
Fluorescence : None
Solubility : -
Magnetism : None
Radioactivity : None