Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
American Mineralogist Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
American Mineralogist; April; v. 94; no. 4; p. 487-493; DOI: 10.2138/am.2009.3060
© 2009 Mineralogical Society of America
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Data Info
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Nestola, F.
Right arrow Articles by Beran, A.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Aluminocerite-Ce: A new species from Baveno, Italy: Description and crystal-structure determination

Fabrizio Nestola1,*, Alessandro Guastoni1, Fernando Cámara2, Luciano Secco1, Alberto Dal Negro1, Danilo Pedron3 and Anton Beran4

1 Dipartimento di Geoscienze, Università di Padova, Via Giotto 1, 35137, Padova, Italy
2 C.N.R., Istituto di Geoscienze e Georisorse, Unità di Pavia, Via Ferrata 1, 27100 Pavia, Italy
3 Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131, Padova, Italy
4 Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria

Correspondence: * E-mail: fabrizio.nestola{at}unipd.it

Aluminocerite-(Ce), ideally (Ce,Ca)9Al(SiO4)3[SiO3(OH)]4(OH)3, is isostructural with cerite-(Ce) and cerite-(La). The holotype was found at the Ratti quarry, near Baveno, Italy, in millimeter-sized secondary cavities hosted in aplite-pegmatite veins and pods within pink granite. Aluminocerite-(Ce) forms aggregates of pseudo-octahedral to rhombohedral crystals flattened on the c axis. The cotype of aluminocerite-(Ce) was discovered at the Locatelly quarry, also near Baveno, where it occurs in centimeter-sized miarolitic cavities in pink granite. The mineral is pale pink to pink-reddish, with a white streak, and is translucent with a vitreous luster. Aluminocerite-(Ce) is non-fluorescent. The hardness based on the Mohs scale is 5, and the tenacity is brittle. Neither cleavage, fracture, or twinning were observed. Calculated density is 4.675 g/cm3. It is uniaxial, optically positive, with no = 1.810–1.816 and ne = 1.812–1.822 ({lambda}= 589 nm) and non-pleochroic. The average of 15 electron microprobe analyses for the holotype gave (wt%): Ce2O3 23.37; Nd2O3 15.59; La2O3 7.43; Sm2O3 4.38; Pr2O3 3.54; Gd2O3 3.12; Y2O3 1.68; Dy2O3 0.46; Yb2O3 0.07; CaO 8.31; Fe2O3 0.47; Al2O3 2.47; SiO2 24.01; and H2O 3.63 (calculated from crystal-chemical constraints), total 98.53 wt%, corresponding to the empirical formula (Ca2.60Ce2.49Nd1.62La0.80Sm0.44Pr0.38Gd0.30Y0.26Dy0.04Yb0.01){sum}8.94(Al0.853+ Fe0.103+){sum}0.95(SiO4)3[SiO3(OH)]4 (OH)3.06, calculated on the basis of Si = 7. Aluminocerite-(Ce) is trigonal, space group R3c, with a =10.645(1), c = 38.019(5) Å, V = 3731 Å3. The strongest eight lines in the X-ray powder diffraction pattern are [d in Å (I)(hkl)]: 3.405(27)(122), 3.250(26)(124), 2.914(100)(02,10), 2.647(58)(220), 2.198(40)(03,12), 1.923(34) (238), 1.826(24)(051), and 1.732(46)(03,18). The crystal structure has been refined to R1 = 0.056 for 745 observed reflections. The name is an allusion to the fact that it is the Al-dominant analog of cerite-(Ce).

Key Words: Aluminocerite-(Ce) • single-crystal XRD • EMP analyses • new mineral • Raman spectroscopy






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Mineralogical Society of America