Donnayite - Encyclopedia

    Class : Carbonates, nitrates, borates
    Subclass : Hydrated carbonates
    Crystal system : Triclinic
    Chemistry : Sr3NaCaY(CO3)6 3H2O
    Rarity : Very rare

Donnayite is an extremely rare complex carbonate which is only known in a few massifs of nepheline syenites and carbonatites and their pegmatites. Its name was given to it in honor of the Belgian crystallographers Joseph Désiré Hubert Donnay and his wife Gabrielle Hamburger Donnay. Donnayite forms small lamellar to tabular crystals, sometimes in barrels which generally do not exceed 2 mm. It is colorless or whitish, gray or yellow, often hooded with mckelveyite.

Main photo : Donnayite from Poudrette Quarry, Mont Saint-Hilaire, Quebec, Canada © Matteo Chinellato

Donnayite from Poudrette Quarry, Mont Saint-Hilaire, Quebec, Canada © Jerry Cone
Donnayite from Poudrette Quarry, Mont St-Hilaire, Quebec, Canada © Elmar Lackner
Donnayite from Poudrette Quarry, Mont St-Hilaire, Quebec, Canada © Dario Cericola
Donnayite from Gloggnitz, Neunkirchen District, Austria © Martin Slama

Donnayite in the World

The best donnayite crystals measure 1 cm and come from Poudrette Quarry (Canada), it is also reported in the pegmatite of Narssârssuk (Greenland), in the carbonatites and pegmatites of the Khibiny Massif (Russia), in the Goudini pegmatite complex (South Africa), Gloggnitz (Austria) and Paratoo copper Mine (Australia).

Donnayite in France

Donnayite is not present in the French underground.

Twinning

No twin known fot this mineral species.

Fakes and treatments

No fake listed for this mineral species.


Hardness : 3
Density : 3.30
Fracture : Undetermined
Streak : White

TP : Translucent to transparent
RI : 1.551 to 1.652
Birefringence : 0.101
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None

Solubility : Acids


Magnetism : None
Radioactivity : None