A mineral assemblage including REE fluorcarbonates (röntgenite-(Ce) Ca2Ce3(CO3)5F3, parisite-(Ce) CaCe2(CO3)3F2, synchisite-(Ce) CaCe(CO3)2F and bastnäsite-(Ce) Ce(CO3)F) was discovered at the dumps of the Vein № 35 open pit, Mt. Dolgaya, Vishnevye Mountains, Southern Urals. These intimately intergrown minerals compose aggregates up to 1 mm in allanite-(Ce)/ferriallanite-(Ce) and chamosite and are associated with microcline, molybdenite, monazite-(Ce), pyrite, thorite, fluorite and fluorannite. The find of röntgenite-(Ce) is first in Urals. Its empirical formula is: (Ca1.98Th0.03) Σ2.01 (Ce1.45La1.02Nd0.32Pr0.11Sm0.03Y0.02Gd0.02)Σ2.97(CO3)5 [F2.48(OH)0.52)Σ3.00. The hexagonal unit cell dimensions of the mineral calculated from X-ray powder data are: a = 7.049(1) Å, c = 69.283(30) Å, V = 2981(1) ų. The strongest bands in the Raman spectrum of the mineral are 164, 250, 349, 606, 731, 867, 1091, 1451 and 1737 cm–1.

Figures 7. Tables 3. References 41.

Key words: vein no. 35, Vishnevye Mountains, REE fluorcarbonates, röntgenite-(Ce), first find
in Urals, parisite-(Ce), synchisite-(Ce), bastnäsite-(Ce).

A.V. Kasatkin, Fersman Mineralogical Museum of RAS, Leninskiy pr. 18/2, Moscow, 119071 Russia; anatoly.kasatkin@gmail.com
R. Škoda, Masaryk University, Kotlářská 2, Brno, 61137 Czech Republic
F. Nestola, University of Padova, Via G. Gradenigo 6, Padova, 35131 Italy 
A.M. Kuznetsov, Oktyabrskaya str., 5-337, Chelyabinsk, 454071 Russia
E.V. Belogub, Institute of Mineralogy SU FRC MG UB RAS, Miass, Chelyabinsk oblast, 456317 Russia
A.A. Agakhanov, Fersman Mineralogical Museum of RAS, Leninskiy pr. 18/2, Moscow, 119071 Russia;

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