Grey inclusions of the extremely rare tantalum mineral alumotantite from the type locality in Russia: Vasin-Myl'k Mountain, Voron'i Tundry, Murmansk Oblast, Russian Federation. Alumotantite occurs as grey inclusions in the one-side polished specimen, mainly inside the circle but also in others parts of the specimen alumotantite can be found. Analyzed specimen by SEM/EDS. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Alumotantite
Alumotantite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula AlTaO₄.
It crystallizes in the orthorhombic crystal system (space group Pbcn).
Key properties: specific gravity 7.48; Adamantine to greasy luster; optically biaxial.
IMA symbol Atan, IMA status: approved, named in 1980.
Found in albitized areas of highly fractionated rare element-enriched granite pegmatites.
It is found associated with Simpsonite, natrotantite, microlite, cesstibtantite, sosedkoite, albite (Kola Peninsula, Russia); simpsonite, manganoan tapiolite, manganotantalite.
The name refers to ALUMinum and TANTalum in the composition.