BURBANKITE

    Class : Carbonates, Nitrates, Borates
    Subclass : Anhydrous carbonates
    Crystal system : Hexagonal
    Chemistry : (Ca,Na)3(Sr,Ba,Ce)3(CO3)5
    Rarity : Very rare

Burbankite is a complex rare-earth carbonate, with a fairly variable chemical composition, frequently associated with ancylite. It is a mineral of silica-deficient rocks, notably nepheline syenites and carbonatites. Its name was given to it in honor of the American geologist Wilbur Sweet Burbank. It forms prismatic crystals grouped in radiated aggregates, as well as centimetric cleavable masses. Burbankite is colorless or grayish yellow, exceptionally pink.

Main photo : Burbankite from Poudrette Quarry, Mont St-Hilaire, Canada © Gianfranco Ciccolini

Burbankite from Poudrette Quarry, Mont St-Hilaire, Canada © Elmar Lackner
Burbankite from Poudrette Quarry, Mont St-Hilaire, Canada © Stephan Wolfsried
Burbankite from Poudrette Quarry, Mont St-Hilaire, Canada © Arnaldo Brunetti
Burbankite from Poudrette Quarry, Mont St-Hilaire, Canada © Elmar Lackner

Burbankite in the World

Burbankite is only known from about fifteen deposits in the world. The best crystals come from the Kirovskii apatite mine (Russia) which provided semi-transparent yellow individuals up to 7 cm. The analcime pegmatite dykes cutting the alkaline syenites of Mont-St-Hilaire (Quebec) yielded stony crystals up to 4 cm and superb small gemmy millimetric crystals. The carbonate stringers intersecting the shonkinites of Big Sandy Creek (Montana) also gave nice millimetric crystals.

Right photo : 2.5 cm Burbankite from Kirovskii Apatite Mine, Russia © Chris Emproto


Burbankite in France

This mineral is not known in the French underground.

Twinning

No known twin for this mineral species.

Fakes and treatments

No fake identified for this mineral species.


Hardness : 3.5 to 4
Density : 3.5 to 3.58
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : 1.597 to 1.635
Birefringence : 0.019
Optical character : Uniaxial -
Pleochroism : Weak
Fluorescence : Violet-blue (rare)

Solubility : Acids

Magnetism : None
Radioactivity : None