Kukharenkoite-(Ce) and its mineral assemblage in pegmatites of the Vishnevye Mountains (South Urals)

Abstract

A rare Ba and REE fuorocarbonate kukharenkoite-(Ce) Ba2Ce(CO3)3F with empirical formu¬la (Ba1.88Sr0.17)2.05(Ce0.53La0.31Nd0.11)0.95(CO3)3F was found in alkali pegmatite of vein no. 35 in the Vishnevye Mountains, South Urals. Kukharenkoite-(Ce) forms small inclusions up to 3–7 µm in anatase and quartz. Raman spectrum of the studied kukharenkoite-(Ce) is similar to spectrum no. R110190 of kukharenkoite-(Ce) from the RRUFF database. The mineral assemblage of pegmatite from vein no. 35 includes feldspars, annite, yangzhuminite (?), aegirine, magnesio-fuoro-arfvedsonite, allanite-(Ce), ilmenite, monazite-(Ce), anatase, rutile, brookite, titanite, pyrite, molybdenite, calcite, zircon, pyrochlore, and REE carbonates – bastnasite-(Ce), parisite-(Ce), synchisite-(Ce), rontgenite-(Ce) and huanghoite-(Ce). Kukharenkoite-(Ce) and, mostly likely, yangzhumingite KMg2. 5[Si4O10]F2 are found for the frst time in the Urals.