FERRIERITE

    Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Orthorhombic
    Chemistry : (Na,K)2MgAl3Si15O36(OH) 9H2O
    Rarity : Rare

Ferrierite belongs to the zeolite group. It is a rare species which fills cracks and cavities in basalts and andesites, as well as interstices in rhyolitic tuffs, associated with calcite and other zeolites. It was named in honor of the Canadian geologist and mining engineer Walter Frederick Ferrier. Ferrierite occurs in lamellar to tabular crystals, frequently elongated along [001] and forming radiate groups that are sometimes spherolitic. They are usually small (0.5 to 1 cm) but can exceptionally reach 8 cm. Ferrierite is colorless, white to pink, sometimes salmon pink. it has one of the smallest densities of zeolites (2.1).

Main photo : Ferrierite from Kamloops Lake, British Columbia, Canada © Rudy W. Tschernich

Ferrierite from Kamloops Lake, British Columbia, Canada © Volker Betz
Ferrierite from Monastir, Sardinia, Italy © Matteo Chinellato
Ferrierite in calcite from Albero Bassi, Veneto, Italy © Antonio Zordan
Ferrierite from Altoona, Washington, USA © Rudy W. Tschernich

Ferrierite in the World

The most beautiful specimens of ferrierite come from British Columbia (Canada), particularly from around Kamloops, where the crystals, generally 5 to 10 mm, can measure up to 8 cm. In Italy, Val Timonchio and Albero Bassi (Veneto) also produce beautiful centimeter-sized crystals and the Monastir deposit (Sardinia) centimeter-sized yellow and orange balls. Ferrierite is also reported in the cavities of many basalts of Australia, Germany, Japan and New Zealand. It is particularly abundant in the tuffaceous sediments of Lovelock, near Oreana (Nevada).

Ferrierite in France

Ferrierite is not present in the French underground.

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 3 to 3.5
Density : 2.13
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : 1.473 to 1.492
Birefringence : 0.004
Optical character : Biaxial (+/-)
Pleochroism : None
Fluorescence : White-blue

Solubility : Hydrochloric acid


Magnetism : None
Radioactivity : None