American Mineralogist, 2004, V 89, N 1.

 LETTER 

239 
Novel phase transition in orthoenstatite 
Jennifer M. Jackson, Stanislav V. Sinogeikin, 
Michael A. Carpenter, and Jay D. Bass 

245 
In situ observation of the thermal decomposition of 
weddelite by heating stage environmental scanning 
electron microscopy 
J. Theo Kloprogge, Thor E. Bostrom, and Matt L. Weier 

ARTICLES 

1
Indialite in xenolithic rocks from Somma-Vesuvius volcano 
(Southern Italy): Crystal chemistry and petrogenetic features 
Giuseppina Balassone, Enrico Franco, Carlo Andrea Mattia, 
and Raffaella Puliti 

7 
Coexisting chromian omphacite and diopside in tremolite 
schist from the Chugoku Mountains, SW Japan: 
The effect of Cr on the omphacite-diopside immiscibility gap 
Tatsuki Tsujimori and Juhn G. Liou 

15 
2111 biopyribole intermediate between pyroxene and 
amphibole: Artifact or natural product? 
Hiromi Konishi, Reijo Alviola, and Peter R. Buseck 

20 
Coexisting clinopyroxene/spinel and amphibole/spinel 
symplectites in metatroctolites from the Buck Creek
ultramafic body, North Carolina Blue Ridge 
Helen M. Lang, Aletha J. Wachter, Virginia L. Peterson, 
and Jeffrey G. Ryan 

31
The T-X dependence of the isosymmetric displacive phase
transition in synthetic Fe3+-Al zoisite: A temperature-dependent
infrared spectroscopy study 
Axel Liebscher and Matthias Gottschalk 

39
A kinetic study of the exsolution of pentlandite (Ni,Fe)9S8 from
the monosulfide solid solution (Fe,Ni)S 
Barbara Etschmann, Allan Pring, Andrew Putnis, Benjamin A. Grguric, 
and Andrew Studer 

51 
Single-crystal plagioclase feldspar dissolution rates measured by
vertical scanning interferometry 
Rolf S. Arvidson, Mikala S. Beig, and Andreas Luttge 

 57 
 A simple empirical method for high-quality electron microprobe 
 analysis of fluorine at trace levels in Fe-bearing minerals and glasses 
Jeffrey B. Witter and Scott M. Kuehner 

 64 
 Constraints on mingling of crystal populations from off-center 
 zoning profiles: A statistical approach 
Glen S. Wallace and George W. Bergantz 

 74 
 Pyribole evolution during tremolite synthesis from oxides 
Krassimir N. Bozhilov, David M. Jenkins, and David R. Veblen 

 85 
 Solution calorimetric determination of the enthalpies of formation 
 of NH4-bearing minerals buddingtonite and tobelite 
Guy L. Hovis, Daniel Harlov, and Matthias Gottschalk 

94 
Dehydration dynamics of bikitaite: Part I. In situ synchrotron
powder X-ray diffraction study 
Orazio Ferro, Simona Quartieri, Giovanna Vezzalini, Chiara Ceriani, 
Ettore Fois, Aldo Gamba, and Giuseppe Cruciani 

102
Dehydration dynamics of bikitaite: Part II. Ab initio molecular dynamics study 
Chiara Ceriani, Ettore Fois, Aldo Gamba, Gloria Tabacchi, Orazio Ferro, 
Simona Quartieri, and Giovanna Vezzalini 

110 
Phosphate mineral associations in the Canada pegmatite (Salamanca, Spain): 
Paragenetic relationships, chemical compositions, and implications
for pegmatite evolution 
Encarnacion Roda, Alfonso Pesquera, Francois Fontan, and Paul Keller 

126
An improved equation for crystal size distribution in second-phase
influenced aggregates 
Alfons Berger 

132 
Vibrational spectroscopy of pyrope-majorite garnets: Structural implications 
A.M. Hofmeister, P.A. Giesting, B. Wopenka, G.D. Gwanmesia, and B.L. Jolliff 

147 The modulated crystal structure of antigorite: The m = 17 polysome 
Giancarlo Capitani and Marcello Mellini 

159 
Structural variations in mercurian tetrahedrite 
Franklin F. Foit Jr. and John M. Hughes 

164 
A computational investigation of the Al/Fe/Mg order-disorder 
behavior in the dioctahedral sheet of phyllosilicates 
Erika J. Palin, Martin T. Dove, Alfonso Hernandez-Laguna, 
and C. Ignacio Sainz-Diaz 

176 
Investigation of Al/Si ordering in tetrahedral phyllosilicate 
sheets by Monte Carlo simulation 
Erika J. Palin and Martin T. Dove 

185 
Equations of state of ZrSiO4 phases in the upper mantle 
Shigeaki Ono, Yoshinori Tange, Ikuo Katayama, 
and Takumi Kikegawa 

189 
High-pressure behavior, transformation and crystal structure
of synthetic iron-free pigeonite 
Fabrizio Nestola, Mario Tribaudino, and Tiziana Boffa Ballaran 

197 
In situ determination of the compressibility of synthetic pure 
zircon (ZrSiO4) and the onset of the zircon-reidite phase transition 
Wim van Westrenen, Mark R. Frank, John M. Hanchar, 
Yingwei Fei, Robert J. Finch, and Chang-Sheng Zha 

204 
Halite-sylvite thermoelasticity 
David Walker, Pramod K. Verma, Lachlan M.D. Cranswick, 
Raymond L. Jones, Simon M. Clark, and Stephan Buhre 

211 
Spiral growth of grossular under hydrothermal conditions 
Ralf Milke 

219 
Incomplete retention of radiation damage in zircon from Sri Lanka 
Lutz Nasdala, Peter W. Reiners, John I. Garver, Allen K. Kennedy,
Richard A. Stern, Etienne Balan, and Richard Wirth 

232 
Shirozulite, KMn32+(Si3Al)O10(OH)2, a new manganese-dominant
trioctahedral mica: Description and crystal structure 
Kiyotaka Ishida, Frank C. Hawthorne, and Fumitoshi Hirowatari 

248 
ERRATUM 
The distribution of zeolites and their effects on the performance of a 
nuclear waste repository at Yucca Mountain, Nevada, U.S.A. 
by D.L. Bish, D.T. Vaniman, S.J. Chipera, and J.W. Carey 
(November-December 2003, vol. 88, no. 11-12, Part 2, 1889-1902). 

249 
NEW MINERAL NAMES 
John L. Jambor, and Andrew C. Roberts 

254 
BOOK REVIEW 
Martine C. Duff 
APPLICATIONS OF SYNCHROTRON RADIATION IN LOW-TEMPERATURE 
GEOCHEMISTRY AND ENVIRONMENTAL SCIENCE. 
P.A. Fenter, M.L. Rivers, N. C. Sturchio, and S.R. Sutton, Eds., 
Reviews in Mineralogy & Geochemistry, 2002, vol. 49, 579 p.
Mineralogical Society of America, Washington, D.C.