RöENTGENITE-(CE) AND OTHER REE FLUORCARBONATES FROM VEIN no. 35, VISHNEVYE MOUNTAINS, SOUTHERN URALS

Abstract

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.

Keywords

• vein no. 35
• vishnevye mountains
• ree fluorcarbonates
• röntgenite-(ce)
• first find in urals
• parisite-(ce)
• synchisite-(ce)
• bastnäsite-(ce)