Pinkish crystals of kuliokite-(Y) in association with albite (white), amazonite (green), and aegirine (black) from the Ploskaya Mt, Kola peninsula, Russian Arctic. The field of view is ca. 2 × 3 mm2. — Photo: Krivovichev, S.V.; Yakovenchuk, V.N.; Goychuk, O.F.; Pakhomovsky, Y.A. · CC BY 4.0
Kuliokite-(Y)
Kuliokite-(Y) is an IMA-recognized mineral species in the silicate class, with the chemical formula Y₄Al(SiO₄)₂(OH)₂F₅.
It crystallizes in the triclinic crystal system (space group P1).
Key properties: Mohs hardness 4–5; specific gravity 4.3; White streak; Adamantine luster; optically biaxial.
IMA symbol Klo-Y, IMA status: approved, named in 1984.
Occurs as inclusions in fluorite or on fissures in microcline pegmatites.
It is found associated with Thalenite, xenotime, kainosite, bastnÄasite, keiviite-(Y), keiviite-(Yb), quartz, fluorite.
The name refers to the Kuliok River, Kola Peninsula, Russia, and yttrium in its composition.