American Mineralogist, V 84, N 1-2, Jan-Feb 1999.

LETTERS

Akihiko Nakatsuka, Akira Yoshiasa, Takamitsu Yamanaka, and Eiji Ito
Structure refinement of birefringent Cr-bearing majorite
Mg3(Mg0.34Si0.34Al0.18Cr0.14)2Si3O12, 
199

Yingwei Fei, Daniel J. Frost, Ho-Kwang Mao, Charles T. Prewitt, and Daniel
Häusermann
In situ structure determination of the high-pressure phase of Fe3O4, 
203

Christian Chateau, Julian Haines, Jean-Michel Léger, André LeSauze, and
Roger Marchand
A moganite-type phase in the silica analog phosphorus oxynitride 
207



ARTICLES

Roger Powell and Tim Holland
Relating formulations of the thermodynamics of mineral solid solutions:
Activity modeling of pyroxenes, amphiboles, and micas 
1

A.A. Graphchikov, A.N. Konilov, and J.D. Clemens
Biotite dehydration, partial melting, and fluid composition: Experiments in
the system KAlO2-FeO-MgO-SiO2-H2O-CO2 
15

F. Holtz, J. Roux, S. Ohlhorst, H. Behrens, and F. Schulze
The effects of silica and water on the viscosity of hydrous
quartzofeldspathic melts 
27

Gregor Markl and Sandra Piazolo
Stability of high-Al titanite from low-pressure calcsilicates in light of
fluid and host-rock composition 
37

Mark J. Davis and Phillip D. Ihinger
New controlled rapid quench technique in a 1 atm infrared image furnace 
48

Alfonso Pesquera, Jose Torres-Ruiz, Pedro P. Gil Crespo, and Nicolas
Velilla
Chemistry and genetic implications of tourmaline and Li-F-Cs micas from the
Valdeflores area (Cáceres, Spain) 
55

Michel Fialin, Hubert Rémy, Claudine Richard, and Christiane Wagner
Trace element analysis with the electron microprobe: New data and
perspectives 
70

Vladimir N. Sobolev, Catherine A. McCammon, Lawrence A. Taylor, Gregory A.
Snyder, and Nikolai V. Sobolev
Precise Mössbauer milliprobe determination of ferric iron in rock-forming
minerals and limitations of electron microprobe analysis 
78

Jean-Louis Robert, Giancarlo Della Ventura, and Frank C. Hawthorne
Near-infrared study of short-range disorder of OH and F in monoclinic
amphiboles 
86

Thomas Armbruster
Si,Al ordering in the double-ring silicate armenite, BaCa2Al6Si9O30•2H2O: A
single-crystal X-ray and 29Si MAS NMR study 
92

Roberta Oberti, Frank C. Hawthorne, Fernando Camara, and Mati Raudsepp
Unusual M3+ cations in synthetic amphiboles with nominal fluro-eckermannite
composition: Deviations from stoichiometry and structural effects of the
cummingtonite component 
102



Giuseppe Cruciani and Alessandro Gualtieri
Dehydration dynamics of analcime by in situ synchrotron powder diffraction
112


Piera Benna, Mario Tribaudino, and Emiliano Bruno
High temperature in situ structural investigation on lead feldspar 
120


Hexiong Yang and Robert M. Hazen
Comparative high-pressure crystal chemistry of karrooite, MgTi2O5, with
different ordering states 
130

Duncan J. Harris, Graeme W. Watson, and Stephen C. Parker
Computer simulation of pressure-induced structural transitions in MgO (001)
tilt grain boundaries 
138

Guntram Jordan, Steven R. Higgins, and Carrick M. Eggleston
Dissolution of the periclase (001) surface: A scanning force microscope
study 
144

R. Lee Penn, Jillian F. Banfield, and Derrill M. Kerrick
TEM investigation of Lewiston, Idaho, fibrolite: Microstructure and grain
boundary energetics 
152

David Schmidt and Kenneth J.T. Livi
HRTEM and SAED investigations of polytypism, stacking disorder, crystal
growth, and vacancies in chlorites from subgreenschist facies outcrops 
160

Junji Akai, Kurumi Akai, Makato Ito, Satoshi Nakano, Yonosuke Make, and
Ichiro Sasagawa
Biologically induced iron-ore at Gunma iron mine, Japan 
171

Barbara Ransom, Richard H. Bennett, Roy Baerwald, Matthew H. Hulbert, and
Patti-Jo Burkett
In situ conditions and interactions between microbes and minerals in
fine-grained marine sediments: A TEM microfabric perspective 
183

NEW MINERAL NAMES 193

BOOK REVIEWS 211

ERRATUM 212