Kukharenkoite-(Ce), Ba2Ce(CO3)3F, a new mineral from Kola peninsula, Russia, and Quebec, Canada
Zaitsev, Anatoly N.; Yakovenchuk, Viktor N.; Chao, George Y.; Gault, Robert A.; Subbotin, Viktor V.; Pakhomosky, Yakοv A.; Bogdanova, Alla N.
European Journal of Mineralogy Volume 8 Number 6 (1997), p. 1327 - 1336
published: Jan 8, 1997
manuscript accepted: Jul 3, 1996
manuscript received: May 2, 1996
ArtNo. ESP147050806011, Price: 29.00 €
Abstract Kukharenkoite-(Ce), ideally Ba2Ce(Co3)3F, is a new rare-earth fluorocarbonate mineral, occurring as an accessory mineral in the late REE-carbonatites and REE-rich carbonate-zeolite rocks of the Khibina massif, Kola peninsula, Russia. It has also been found in other associations within the Khibina complex as well as in the Vuorijärvi massif, Kola peninsula and the related alkaline intrusions of the Mont Saint-Hilaire complex and the Saint-Amable sill, Quebec, Canada. Kukharenkoite-(Ce) occurs in cavities as small (0.01-1.0 mm), prismatic, bladed crystals which are often in dendritic or stellate groups up to 2-3 mm across. Associated minerals are manganoan ankerite, ferroan rhodochrosite, manganoan siderite, natrolite, synchysite-(Ce), orthoclase, barite, pyrite, cordylite-(Ce), mckelveyite-(Y), ewaldite, galena and sphalerite. The mineral is yellow with a white streak; transparent with a vitreous lustre. Cleavage and parting were not observed. The microhardness VHN25 is 280(25), the Mohs hardness is 4.5; density (meas.) is 4.7(1) g/cm3 and density (calc.) is 4.62 g/cm3. The infrared absorption spectrum includes the following bands: v4 685-695-705-715-735; v2 870-885; V1 1090; v3 1380-1430-1480 cm-1. It is optically biaxial (-), with α 1.584(1), ß 1.724(3), γ 1.728(3) (for Na light), 2Vmeas.: 16(1)°, 2Vcaic.: 18(1)°, ZΛc = 26.5° in obtuse ß, Y = b. On the Khibina specimens, an average of 12 electron-microprobe analyses gave CaO 0.39, SrO 1.55, BaO 47.39, La2O3 6.61, Ce2O3 15.30, Pr2O3 1.19, Nd2O3 4.26, Y2O3 0.15, CO2 21.95 (calculated by stoichiometry), F 3.18, -O = F2 1.34, total 100.63. The ideal formula is Ba2Ce(CO3)3F. The mineral is monoclinic, P21/m, with a 13.396(7), b 5.067(1), c 6.701(1) Å, ß 106.58(1)° , V 435.8(3) Å3, Z= 2. The strongest five X-ray powder diffraction lines [d in Å(I)(hkl)] are: 4.000(100)(201), 3.269(100)(310), 2.535(20X020), 2.140(40X221), 2.003(40X402). The name kukharenkoite-(Ce) is given in honour of Professor A.A. Kukharenko (1914-1993; Department of Mineralogy, St-Petersburg University, Russia).