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 in the World
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