Original paper

L'astrocyanite-(Ce), Cu2(TR)2(UO2)(CO3)5(OH)2.1,5 H2O, nouvelle espèce minérale de Kamoto, Shaba, Zaire

Deliens, Michel; Piret, Paul

European Journal of Mineralogy Volume 2 Number 3 (1990), p. 407 - 412

7 references

published: Jun 21, 1990
manuscript accepted: Jan 16, 1990
manuscript received: Oct 13, 1989

DOI: 10.1127/0009.407

BibTeX file

ArtNo. ESP147050203009, Price: 29.00 €

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Abstract

Abstract : Astrocyanite-(Ce) occurs as bright blue millimetric rosettes on uraninite matrix in the Cu-Co deposit of East Kamoto, southern Shaba, Zaire. Associated minerals are other uranium and rare-earth secondary minerals such as kamotoite-(Y), shabaite-(Nd) and françoisite-(Nd). Optically uniaxial negative with ω = 1.688 and e = 1.638. Strong pleochroism bright blue (ω) to nearly colourless (e). Hexagonal, space group P6/mmm,P6mm, P622, P6̅2m or P6̅m2, a = 14.96, c = 26.86 Å, V = 5206 Å3, Z = 12, dcalc. = 3.95 g/cm3, dmeas. = 3.80 g/cm3. Strongest lines in the X-ray powder pattern: [d(Å),(I),hkl]: 6.73 (10) 004, 3.72 (9) 220, 4.16 (6) 205, 4.30 (5) 300 and 13.3 (4) 002. Electron microprobe analyses yield: CuO 15.55, UO3 28.16, CaO 0.61, Ce2O3 11.83, Nd2O3 9.74, La2O3 3.38, Pr2O3 2.48, Sm2O3 2.00, Y2O3 0.15, CO2 (by chromatography) 21.40 and H2O (by difference) 4.70 %. Ideal formula: Cu2(REE)2(UO2)(CO3)5(OH)2. 1.5 H2O. The name is for the morphology, the colour and the dominant lanthanide element.

Keywords

new mineralastrocyanite-(Ce)uranyl carbonateKamotoZaire