Kupletskite- Encyclopedia
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 in the World
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