Kukharenkoite-(Ce), Ba (sub 2) Ce(CO (sub 3) ) (sub 3) F, a new mineral from Kola Peninsula, Russia, and Quebec, Canada

Kukharenkoite-(Ce) is a new rare-earth fluorocarbonate occurring as an accessory mineral in the late REE-carbonatites and REE-rich carbonate-zeolite rocks of the Khibina massif; it has also been found in other associations both in the Khibina and Vuorjaervi massifs of the Kola Peninsula, and in the alkaline intrusions of Mont Saint Hilaire complex and Saint-Amable sill, Quebec. Kukharenkoite-(Ce) is found in cavities as small (0.01-1.0 mm), prismatic, bladed crystals which may form stellate groups; associated minerals include manganoan ankerite, ferroan rhodochrosite, manganoan siderite, natrolite, synchisite-(Ce), orthoclase, baryte, pyrite, cordylite-(Ce), mckelveyite-(Y), ewaldite, galena and sphalerite. It is yellow with a white streak; transparent with a vitreous lustre; no cleavage or parting; VHN (sub 25) 280 (H. 4.5); D 4.71 g/cm (super 3) ; the IR spectrum is presented. It has alpha 1.584, beta 1.724, Gamma 1.728, 2V<F128MV>a<F255D>16 degrees , Gamma :c 26.5 degrees in obtuse beta , beta = b. The average of 12 EPMA results for the Khibina material gave CaO 0.39, SrO 1.55, BaO 47.39, La (sub 2) O (sub 3) 6.61, Ce (sub 2) O (sub 3) 15.30, Pr (sub 2) O (sub 3) 1.19, Nd (sub 2) O (sub 3) 4.26, Y (sub 2) O 0.15, CO (sub 2) 21.95, F 3.18, less O = F 1.34, = 100.63, leading to the ideal formula Ba (sub 2) Ce(CO (sub 3) ) (sub 3) F. The indexed XRD powder pattern is tabulated; strongest lines 4.000(100), 3.269(100), 2.140(40), 2.003(40), 2.535(20) Aa; a 13.396, b 5.067, c 6.701 Aa, beta 106.58 degrees , V 435.8 Aa (super 3) , Z = 2. The name is for Professor A.A. Kukharenko (1914-1993), Dept. of Mineralogy, St Petersburg University.