KUPLETSKITE

    Class : Silicates
    Subclass : Inosilicates
    Crystal system : Triclinic
    Chemistry : (K,Na)3(Mn,Fe)7(Ti,Nb)2Si8O24(O,OH)7
    Rarity : Rare to very rare

Kupletskite is a complex silicate from the astrophyllite group. It is a rare mineral of nepheline syenites and their pegmatites, and more generally of complexes of alkaline magmatic rocks. It forms two series with astrophyllite and cesium-kupletskite. It was named in honor of two Russian geologists : Boris Mikhailovich Kupletskaya and Elsa Maxilianovna Bonshtedt-Kupletskaya. Kupletskite occurs in tabular to acicular crystals and in lamellar masses with a radiated texture, measuring up to 5 cm, of a yellow-orange color when fresh, browning then blackening by the formation of a surface film of oxides of manganese.

Main photo : Kupletskite from Poudrette Quarry, Mont St-Hilaire, Quebec, Canada © Modris Baum

Kupletskite from Poudrette Quarry, Mont St-Hilaire, Quebec, Canada © Jeffrey de Fourestier
Kupletskite from Big Rock Quarry, Arkansas, USA © Steve Stuart
Kupletskite from Poudrette Quarry, Mont St-Hilaire, Quebec, Canada © Jason B. Smith
Kupletskite from Big Rock Quarry, Arkansas, USA © Stephan Wolfsried

Kupletskite in the World

Kupletskite is known in several alkaline massifs, notably the nepheline syenites of Greenland (Ilimaussaq complex in Narssaq), the Kola peninsula (Lovozero), and Mont St-Hilaire (Canada).

Kupletskite in France

Kupletskite is not present in the French underground.

Twinning

No twins are known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 3 to 4
Density : 3.20 to 3.36
Fracture : Undetermined
Streak : Brown

TP : Translucent
RI : 1.656 to 1.734
Birefringence : 0.075
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None