FAUJASITE

    Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Cubic
    Chemistry : (Na2,Ca)Al2Si4O12 8H2O
    Rarity : Very rare

Faujasite is a very rare zeolite, the one whose structure is the most airy due to very spacious channels. Its deposit is classic for a zeolite : it is found in the vacuoles of basalts, sometimes phonolites and more rarely in altered volcanic tuffs. It was named in honor of the French mineralogist and volcanologist Barthélémy Faujas de St Fond. Faujasite forms octahedral crystals of 4 mm at most, frequently agglomerated into centimeter-sized aggregates. It is colorless, white, bluish or light brown.

Main photo : Twinned faujasite from Limberg Quarries, Sasbach am Kaiserstuhl, Baden-Württemberg, Germany © Volker Betz

Faujasite from Limberg Quarries, Baden-Württemberg, Germany © Volker Betz
Faujasite from Maykranz Quarry, Hesse, Germany © Wolfgang Stoll
Faujasite from Limberg Quarries, Baden-Württemberg, Germany © Volker Betz
Faujasite, phillipsite and chabazite from Collet, Haute-Loire, France © J.-M. Boisson

Faujasite in the World

The Kaiserstuhl (Baden-Württemberg, Germany) is the main global location for this rare zeolite, which is also present in the Vogelsberg Mountains, also in Germany. Faujasite is also found in Sicily near Catania (Italy), and in Canada in Ontario (Bancroft and Khartoum), and Quebec (Ottawa County).

Faujasite in France

In France, faujasite-Ca was reported at Le Collet near Araules (Haute-Loire) and faujasite-Na was identified during work on RD 537 near Rodez (Aveyron) associated with chabazite and phillipsite. It is also found in Mururoa on the Tuamotu Archipelago in French Polynesia.

Twinning

Spinel twins are quite common and can be multiple.

Fakes and treatments

No fake listed for this mineral species.


Hardness : 5
Density : -
Fracture : Undeterminated
Streak : White

TP : Transparent
RI : -
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None

Solubility : -


Magnetism : None
Radioactivity : None