CLINOFERROSILITE

    Class : Silicates
    Subclass : Inosilicates
    Crystal system : Monoclinic
    Chemistry : FeSiO3
    Rarity : Very rare

Clinoferrosilite belongs to the group of pyroxenes. It is a rare dimorph of ferrosilite which forms a continuous series with clinoenstatite. Its name is related to its monoclinic crystal system and its chemical similarity to ferrosilite. It is found in acicular crystals barely millimetric in size, black to dark green or slightly brown in color.

Main photo : Clinoferrosilite on amethyst from Sant'Antioco, Sardinia, Italy © Christophe Boutry

Clinoferrosilite in the World

Clinoferrosilite is very rare, it is practically only known in obsidian lithophyses at Lake Naivasha (Kenya), and at Obsidian Cliff, in Yellowstone Park (Wyoming, USA). Its best crystals, millimeter-sized, come from the vacuoles of the rhyolite of Sant'Antioco (Sardinia, Italy).

Right photo : Clinoferrosilite from Sant'Antioco, Sardinia, Italy © Henk Smeets

Clinoferrosilite in France

Clinoferrosilite is not known in the French underground.

Twinning

No twin known for this mineral species.

Fakes and treatments

No fake identified for this mineral species.


Hardness : 5 to 6
Density : 4.07
Fracture : Conchoidal
Streak : White

TP : Translucent to transparent
RI : 1.764 to 1.792
Birefringence : 0.028
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : Insoluble


Magnetism : Paramagnetic
Radioactivity : None