Lavendulan - Encyclopedia
Class : Phosphates, arsenates, vanadates
Subclass : Hydrated arsenates
Crystal system : Orthorhombic
Chemistry : NaCaCu5(AsO4)4Cl 5H2O
Rarity : Uncommon to fairly common
Lavendulan (or lavendulanite) is a complex arsenate from the oxidation zone of certain copper deposits. It is also found in industrial slag. It is a fairly common mineral which is systematically associated with other secondary copper minerals (brochantite, malachite, cuprite, etc...) and with sulphides in the process of alteration, notably tennantite. Its name refers to its lavender color. Lavendulan closely resembles sampleite : flattened to lamellar crystals not exceeding 3 mm, frequently grouped in rosettes or radiated spherolites, of a beautiful light greenish blue to deep blue color. Lavendulanite also constitutes botryoidal encrustations.
Main photo : Lavendulan from Preamimma Mine, Callington, Australia © Jean-Pierre Barral
Lavendulan in the World
Twinning
Twins are common for this mineral species.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 2.5
Density : 3.54
Fracture : Undetermined
Streak : Blue
TP : Translucent
RI : 1.660 to 1.734
Birefringence : 0.074
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : None