TUNISITE

    Class : Carbonates, nitrates, borates
    Subclass : Anhydrous carbonates
    Crystal system : Tetragonal
    Chemistry : NaCa2Al4(CO3)4(OH)8Cl
    Rarity : Rare

Tunisite is a carbonate from the oxidation zone of hydrothermal veins with calcite matrix. Its name comes from its country of discovery : Tunisia. Tunisite usually occurs in crystalline aggregates composed of tiny (less than 0.2 mm) colorless or white crystals; however, tabular macroscopic crystals measuring up to 8 mm are known, gathered in parallel aggregates.

Main photo : Tunisite from Condorcet, Drôme, France © Gianfranco Ciccolini

Tunisite in the World

A very rare mineral, tunisite is known in the waste dumps of the old Sakiet Sidi Youssef mine (Tunisia).

Tunisite in France

In France, tunisite is present in millimetric crystals in the septarias near the old lead-zinc mine of Condorcet (Drôme) associated with whewellite, calcite and celestite, these are undoubtedly the best samples in the world.

Right photo : Tunisite from Condorcet, Drôme, France © Stéphane Maury

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 4.5
Density : 5.51
Fracture : Undetermined
Streak : White

TP : Transparent
RI : 1.573 to 1.599
Birefringence : 0.026
Optical character : Uniaxial +
Pleochroism : None
Fluorescence : None

Solubility : Hydrochloric acid

Magnetism : NoneRadioactivity : None