American Mineralogist, 2005, V 90, N 4, April.

     
LETTERS 

745
Growth zoning and strain patterns inside diamond
 crystals as revealed by Raman maps 
Lutz Nasdala, Wolfgang Hofmeister, 
Jeffrey W. Harris, and Jurgen Glinnemann 

749 
Differentiation of commercial vermiculite 
based on statistical analysis of bulk chemical
data: Fingerprinting vermiculite from Libby, Montana U.S.A. 
Mickey E. Gunter, Eron Singleton,
Bryan R. Bandli, Heather A. Lowers, and Gregory P. Meeker 

755 
Crystal structure of single-crystal CaGeO3 
tetragonal garnet synthesized at 3 GPa and 1000 °C 
Akihiko Nakatsuka, Hiroki Chaya, and Akira Yoshiasa 

758 
Iron isotope exchange kinetics at the nanoparticulate 
ferrihydrite surface 
Rebecca L. Poulson, Clark M. Johnson, and Brian L. Beard 

764 
Cation distribution in MgFe2O4 vs. pressure and 
temperature: Experiments in a "piston-cylinder" apparatus 
Alexander I. Turkin and Valeri A. Drebushchak 


MONAZITE GEOCHRONOLOGY
 

525
Preface to collected papers on monazite 
microprobe geochronology 
Michael L. Williams and Robert J. Tracy 

526
Analytical perils (and progress) in electron
microprobe trace element analysis applied to 
geochronology: Background acquisition, 
interferences, and beam irradiation effects 
Michael J. Jercinovic and Michael L. Williams 

547 
Contributions to precision and accuracy of 
monazite microprobe ages 
Joseph M. Pyle, Frank S. Spear, David A. Wark, 
Christopher G. Daniel, and Lara C. Storm 

578 
Electron-microprobe age mapping of monazite 
Philippe Goncalves, Michael L. Williams, 
and Michael J. Jercinovic 

586 
Isotopic age constraints from electron microprobe
U-Th-Pb dates, using a three-dimensional concordia diagram 
Yvette D. Kuiper 

592 
Monazite ages in the Chesham Pond Nappe, SW 
New Hampshire, U.S.A.: Implications for assembly of 
central New England thrust sheets 
Joseph M. Pyle, Frank S. Spear, John T. Cheney, 
and Graham Layne 

607 
Electron-microprobe dating as a tool for
determining the closure of Th-U-Pb systems 
in migmatitic monazites 
Alain Cocherie, Eug¦ne be Mezeme, 
Olivier Legendre, C. Mark Fanning, Michel Faure, 
and Philippe Rossi 

619 
Comparative isotopic and chemical geochronometry
of monazite, with implications for U-Th-Pb 
dating by electron microprobe: An example 
from metamorphic rocks of the eastern 
Wyoming craton (U.S.A.) 
Peter S. Dahl, Michael A. Hamilton, 
Michael J. Jercinovic, Michael P. Terry, 
Michael L. Williams, and Robert Frei 

ARTICLES 

  639 Re-examination of the hydrogarnet 
structure at high pressure using neutron
powder diffraction and infrared spectroscopy 
George A. Lager, William G. Marshall, 
Zhenxian Liu, and Robert T. Downs 
   
        
645 
Anomalous elastic behavior and high-pressure 
structural evolution of zeolite levyne 
Giacomo Diego Gatta, Paola Comodi, 
Pier Francesco Zanazzi, and Tiziana Boffa Ballaran 

653 
Crystal chemistry of the hydrothermally 
synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution 
Frederic Hatert, Leila Rebbouh, Raphael P. Hermann, 
Andre-Mathieu Fransolet, Gary J. Long, and Fernande Grandjean 

663 
Thermodynamic properties of uvarovite garnet (Ca3Cr2Si3O12) 
S. Klemme, J.C. van Miltenburg, P. Javorsky, and F. Wastin 

667 
Post-aragonite phase transformation in CaCO3 at 40 GPa 
Shigeaki Ono, Takumi Kikegawa, Yasuo Ohishi, 
and Jun Tsuchiya 

672 
Direct formation of the ?-CaSO4 phase in 
dehydration process of gypsum: In situ FTIR study 
P.S.R. Prasad, V. Krishna Chaitanya, K. Shiva Prasad, 
and D. Narayana Rao 

679 
The order-disorder character of FeOHSO4 obtained 
from the thermal decomposition of metahohmannite, 
Fe3+2(H2O)4[O(SO4)2] 
Gennaro Ventruti, Fernando Scordari, 
Emanuela Schingaro, Alessandro F. Gualtieri, 
and Carlo Meneghini 

687 
Temperature and composition dependence of 
structural phase transitions in Ca(TixZr1-x)OGeO4 
Rikke Ellemann-Olesen and Thomas Malcherek 

695 
Low-T neutron powder-diffraction and 
synchrotron-radiation IR study of synthetic 
amphibole Na(NaMg)Mg5Si8O22(OH)2 
G. Iezzi, G.D. Gatta, W. Kockelmann, 
G. Della Ventura, R. Rinaldi, W. Schafer, 
M. Piccinini, and F. Gaillard 

701 
Charge contrast imaging of fine-scale microstructure 
and compositional variation in garnet using the 
environmental scanning electron microscope 
Simon J. Cuthbert and James O. Buckman 

708 
Piston-cylinder experiments on H2O undersaturated
Fe-bearing systems: An experimental setup approaching
?O2 conditions of natural calc-alkaline magmas 
Ralf Kagi, Othmar Muntener, Peter Ulmer, and Luisa Ottolini 

718 
Environmentally important, poorly crystalline 
Fe/Mn hydrous oxides: Ferrihydrite and a possibly
 new vernadite-like mineral from the Clark 
Fork River Superfund Complex 
Michael F. Hochella, Jr., Takeshi Kasama, 
Andrew Putnis, Christine V. Putnis, and 
Johnnie N. Moore 

725
The true structure of wonesite, an interlayerdeficient
trioctahedral sodium mica 
Toshihiro Kogure, Ritsuro Miyawaki, and Yasuyuki Banno
 
732 
Clinoholmquistite discredited: The new amphibole
end-member fluoro-sodic-pedrizite 
Roberta Oberti, Fernando Camara, and Luisa Ottolini 

737 
XRMapAnal: A program for analysis of quantitative X-ray maps 
Douglas K. Tinkham and Edward D. Ghent 

768 
NEW MINERAL NAMES 
Paula C. Piilonen, T. Scott Ercit, And Andrew C. Roberts 

774
 BOOK REVIEW 
DEER, HOWIE AND ZUSSMAN ROCK-FORMING MINERALS, 
SHEET SILICATES: MICAS, volume 3A, 2nd edition. 
By M.E. Fleet, The Geological Society, London, 2003, 758 pp. 
Stephen Guggenheim 

776 
ERRATUM 
The Mn, Mg-intracrystalline exchange reaction in
donpeacorite (Mn0.54Ca0.03Mg1.43Si2O6) and 
its relation to the fraction- ation behavior 
of Mn in Fe, Mg-orthopyroxene
by Marilena Stimpfl (2005, vol. 90, p. 155-161,