Original paper

Calcio-ancylite-(Nd), a new REE-carbonate from Baveno, Italy

Orlandi, Paolo; Pasero, Marco; Vezzalini, Giovanna

European Journal of Mineralogy Volume 2 Number 3 (1990), p. 413 - 418

17 references

published: Jun 21, 1990
manuscript accepted: Mar 16, 1990
manuscript received: Oct 27, 1989

DOI: 10.1127/ejm/2/3/0413

BibTeX file

ArtNo. ESP147050203010, Price: 29.00 €

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Abstract

Abstract Calcio-ancylite-(Nd), a new basic hydrated carbonate of calcium and REE, occurs as pink pine-cone-like crystals in miarolitic cavities of Baveno granite, Italy. Electron microprobe analysis yields the formula: (Nd0.90Ce0.64Sm0.33Gd0.28Y0.26Pr0.15La0.14Dy0.07Tm0.03)Σ=2.80Ca1.20(CO3)3.98(OH)2.84,1.01H2O (Z = 1). The mineral is monoclinic, Pm11, with a = 4.976(2), b = 8.468(2), c = 7.212(2) Å, α = 90.04(3)° ; dmeas > 4.02 and dcalc = 4.08 g/cm3; hardness (Mohs) 4-4.5 ; biaxial ( - ) . The three strongest lines of the X-ray powder diffraction pattern are [d (Å), (hkl), I] : 4.26, (100), 100 ; 2.905, (102), 90 ; 2.048, (221), 80. The crystal structure refinement (Rw = 0.036) confirms the main features of ancylite-(Ce), but provides evidence for a different distribution of alkaline earth and REE in the M sites. A re-examination of the discredited mineral "weibyeite" from Baveno shows that it is a calcio-ancylite-(Ce) with variable REE content.

Keywords

calcio-ancylite-(Nd)carbonatecrystal structureItaly"weibyeite"