Brown agregate of tabular beta-Fergusonite-(Y) crystals associated with orange Zircon, black Ferriallanite-(Ce), white Kainosite-(Y) and glassy Quartz into apoeudialyte pseudomorphose. FOV 10x8 mm. Note special nontetragonal and nonbipyramidal morphology of xls and theyr "dry" lustre so characteristic for nonmetamict niobates. X-ray identification of not heated specimen. Composition of the mineral is - (Y0.70HREE0.23LREE0.04Ca0.01)0.98(Nb0.97Ta0.02Ti0.01)1.00O3.90(OH)0.10. Its REE spectrum has Dy maximum. Pavel M. Kartashov analysis, collection and photo; Locality: Neprimetnyi pegmatite, Mount Ulyn Khuren, Khaldzan Buragtag Massif, Altai Mts, Hovd Aimag, Mongolia;
Copyright: Pavel M. Kartashov