Indialite - Encyclopedia

    Class : Silicates
    Subclass : Cyclosilicates
    Crystal system : Hexagonal
    Chemistry : Mg2Al4Si5O18
    Rarity : Very rare


Indialite is a dimorphic silicate of cordierite. Much rarer than the latter, indialite is formed in sedimentary rocks melted by the spontaneous combustion of coal seams. It is also known in cordierite veins in a highly metamorphic andalusite and sillimanite rock (Unazuki, Japan). Its name comes from its country of discovery : India. It forms small hexagonal grains and small spiral aggregates that are colorless to pale purplish pink.

Main photo : Indialite from Caspar quarry, Bellerberg, Germany © Volker Betz

Indialite by Nickenicher Weinberg, Eifel, Germany © Volker Betz
Indialite by Nickenicher Weinberg, Eifel, Germany © Volker Betz
Indialite by Nickenicher Weinberg, Eifel, Germany © Volker Betz
Indialite of Vesuvius, Naples, Italy © Christophe Boutry

Indialite in the World

Occurrences of indialite are very rare. In addition to that of Unazuki (Japan), it is known in a "molten" rock with enstatite, magnetite and corundum in contact with a consumed coal mine in Bokaro (India). Rare other localities are also reported, notably in Germany (Bellerberg volcano) and in the United States (Pyramid Lake, Nevada).

Indialite in France

Indialite is not present in the French underground.

Twinning

No twins known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.



Hardness : 7 to 7.5
Density : 2.51
Fracture : Undeterminated
Streak : White


TP : Transparent
RI : 1.534 to 1.539
Birefringence : 0.005
Optical character : Uniaxial -
Pleochroism : None
Fluorescence : None


Solubility : -


Magnetism : NoneRadioactivity : None