Aeschynite - Encyclopedia

    Class : Oxides and hydroxides
    Subclass : Oxides
    Crystal System : Orthorhombic
    Chemistry : (Ce,Ca,Fe,Th)(Ti,Nb)₂(O,OH)₆
    Rarity : Very rare

Aeschynite is now considered a group of complex oxides of titanium and niobium, subdivided into three minerals according to the dominant metal : aeschynite-(Ce), aeschynite-(Nd) and aeschynite-(Y). Its name comes from the Greek aeschyne (shame) because when it was discovered in 1828, chemists were unable to separate all its constituents. Aeschynite is a rare oxide of nepheline syenites, and more generally of alkaline syenites, more rarely of carbonatites and granitic pegmatites. Very resistant to weathering, it concentrates well in the placers. It is a black to yellow-brown mineral, often radioactive due to the fairly common presence of thorium (up to 30% ThO₂), its crystals are striated, prismatic to tabular. It is a potential ore of thorium, tantalum, niobium and rare earth elements. Photo © Giuseppe Finello

Aeschynite-(Y) is present in France in microcrystals in certain alpine fissures, notably at Plan-du-Lac (Isère) associated with anatase, at the Grand Pic and the Pointe du Rozet (Savoie), in the Madone valley. des Fenestres (Alpes-Maritimes) and in the talc quarry of Trimouns (Ariège).

Photo © Michel Bretheau: aeschynite-(Y) needles on Trimouns dolomite, Ariège, France

No known twin for this mineral species.

No known fakes or treatments.