NÉPOUITE

    Class : Silicates
    Subclass : Phyllosilicates
    Crystal system : Orthorhombic
    Chemistry : Ni3Si2O5(OH)4
    Rarity : Quite common

Népouite is a rare nickel silicate belonging to the serpentine group ; it forms a continuous series with lizardite. It is a secondary mineral formed by alteration of peridotites and dunites rich in nickel which enters into the constitution of "garnierites", these nickel-bearing silicates exploited as nickel ore. It was named in reference to its place of discovery : the Reis II mine in Népoui (New Caledonia). Népouite is a light to dark green mineral, the intensity of the green depending on the nickel content, a metal that iron and magnesium can replace in significant proportions.

Main photo : Népouite from Népoui Mine, New Caledonia © Lee Johnson

Népouite in the World

Nepouite is found in nickel-bearing laterites and chromite serpentinites in many localities around the world, including localities with chrome-bearing ultrabasic rocks in California. It is also found in particular in Pafuri and Barberton (South Africa), and in Letovice (Czech Republic).

Népouite in France

In France, Népouite is known in numerous nickel mines in New Caledonia in Nouméa, Nakety, Népoui, etc...

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 2 to 2.5
Density : 3.24
Fracture : Irregular
Streak : White-green

TP : Translucent to opaque
RI : 1.576 to 1.650
Birefringence : 0.027
Optical character : Biaxial -
Pleochroism : Low
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None