946

Evidence for anomalously large degree of polymerization in Mg₂SiO₄ glass and melt
Sabyasachi Sen and Jean Tangeman

950

Theoretical infrared absorption coefficient of OH groups in minerals
Etienne Balan, Keith Refson, Marc Blanchard, Simon Delattre, Michele Lazzeri, Jannick Ingrin, Francesco Mauri, Kate Wright, and Bjoern Winkler

713

The crystal structure of vurroite, Pb₂₀Sn₂(Bi,As)₂₂S₅₄Cl₆: OD-character, polytypism, twinning, and modular description
Daniela Pinto, Elena Bonaccorsi, Tonci Balić-Žunić, and Emil Makovicky

728

Mineralogy of the Paso Robles soils on Mars
Melissa D. Lane, Janice L. Bishop, M. Darby Dyar, Penelope L. King, Mario Parente, and Brendt C. Hyde

740

Dingdaohengite-(Ce) from the Bayan Obo REE-Nb-Fe Mine, China: Both a true polymorph of perrierite-(Ce) and a titanic analog at the C1 site of chevkinite subgroup
Jinsha Xu, Guaming Yang, Guowu Li, Zhilan Wu, and Ganfu Shen

745

Thermal equation of state of CaGeO₃ perovskite
Wei Liu, Jennifer Kung, Liping Wang, and Baosheng Li

751

Quantitative absorbance spectroscopy with unpolarized light: Part I. Physical and mathematical development
Malcolm Sambridge, John Fitz Gerald, István Kovács, Hugh St.C. O’Neill, and Jörg Hermann

765

Quantitative absorbance spectroscopy with unpolarized light: Part II. Experimental evaluation and development of a protocol for quantitative analysis of mineral IR spectra
Istv‡n Kov‡cs, Jšrg Hermann, Hugh St.C. O’Neill, John Fitz Gerald, Malcolm Sambridge, and G‡bor Horv‡th

779

Oxide-melt solution calorimetry of selenides: Enthalpy of formation of zinc, cadmium, and lead selenide
Suraj Deore, Fen Xu, and Alexandra Navrotsky

784

Precise dating of biotite in distal volcanic ash: Isolating subtle alteration using ⁴⁰Ar/³⁹Ar laser incremental heating and electron microprobe techniques
M. Elliot Smith, Brad S. Singer, Alan R. Carroll, and John H. Fournelle

796

Rationale for the existence of four- and eight-reversals in antigorite
Gian Carlo Capitani and Marcello Mellini

800

Structural relaxation around substitutional Cr³⁺ in pyrope garnet
Amélie Juhin, Georges Calas, Delphine Cabaret, Laurence Galoisy, and Jean-Louis Hazemann

806

Metasomatic thorite and uraninite inclusions in xenotime and monazite from granitic pegmatites, Hidra anorthosite massif, southwestern Norway: Mechanics and fluid chemistry
Callum J. Hetherington and Daniel E. Harlov

821

Interlayer potassium and its neighboring atoms in micas: Crystal-chemical modeling and XANES spectroscopy
Maria Franca Brigatti, Daniele Malferrari, Marco Poppi, Annibale Mottana, Giannantonio Cibin, Augusto Marcelli, and Gianfelice Cinque

831

Effect of chemical environment on the hydrogen-related defect chemistry in wadsleyite
Yu Nishihara, Toru Shinmei, and Shun-ichiro Karato

844

Fracture toughness, hardness, and elastic modulus of kyanite investigated by a depth-sensing indentation technique
Alexandre Mikowski, Paulo Soares, Fernando Wypych, and Carlos M. Lepienski

853

Crystal chemistry of the natrojarosite-jarosite and natrojarosite-hydronium jarosite solid-solution series: A synthetic study with full Fe site occupancy
Laurel C. Basciano and Ronald C. Peterson

863

A new experimental thin film approach to study mobility and partitioning of elements in grain boundaries: Fe-Mg exchange between olivines mediated by transport through an inert grain boundary
Ralf Dohmen

875

Titanium as a cathodoluminescence activator in alkali feldspars
Ian Parsons, David A. Steele, Martin R. Lee, and Charles W. Magee

880

Biogenic vs. abiogenic magnetite nanoparticles: A XMCD study
Claire Carvallo, Philippe Sainctavit, Marie-Anne Arrio, Nicolas Menguy, Yuheng Wang, Georges Ona-Nguema, and Sandrine Brice-Profeta

886

Solubility of andradite, Ca₃Fe₂Si₃O₁₂, in a 10 mol% NaCl solution at 800 °C and 10 kbar: Implications for the metasomatic origin of grandite garnet in calc-silicate granulites
Jeremy L. Wykes, Robert C. Newton, and Craig E. Manning

893

A 3D reconstruction of plagioclase crystals in a synthetic basalt
Stéphanie Duchêne, Elsa Pupier, Christian Le Carlier De Veslud, and Michael J. Toplis

902

Rudashevskyite, the Fe-dominant analogue of sphalerite, a new mineral: Description and crystal structure
Sergey N. Britvin, Alla N. Bogdanova, Maya M. Boldyreva, and Galina Y. Aksenova

910

Birchite, a new mineral from Broken Hill, New South Wales, Australia: Description and structure refinement
Peter Elliott, Joël Brugger, Allan Pring, Marcus L. Cole, Anthony C. Willis, and Uwe Kolitsch

918

Crystal structure of synthetic Al₄B₂O₉: A member of the mullite family closely related to boralsilite
Reinhard X. Fischer, Volker Kahlenberg, Dietmar Voll, Kenneth J.D. MacKenzie, Mark E. Smith, Bernhard Schnetger, Hans-Jürgen Brumsack, and Hartmut Schneider

928

Interaction of gypsum with As(V)-bearing aqueous solutions: Surface precipitation of guerinite, sainfeldite, and Ca₂NaH(AsO₄)₂·6H₂O, a synthetic arsenate
Juan D. Rodríguez, Amalia Jiménez, Manuel Prieto, Laura Torre, and Santiago García-Granda

940

Jahnsite-(NaFeMg), a new mineral from the Tip Top mine, Custer County, South Dakota: Description and crystal structure
Anthony R. Kampf, Ian M. Steele, and Thomas A. Loomis

954

Presentation of the Roebling Medal for 2007 of the Mineralogical Society of America to Gordon E. Brown Jr.
G.V. Gibbs and Michael F. Hochella Jr.

956

Acceptance of the Mineralogical Society of America Roebling Medal for 2007
Gordon E. Brown Jr.

958

Presentation of the Mineralogical Society of America Award for 2007
Simon Redfern

959

Acceptance of the Mineralogical Society of America Award for 2007
Richard J. Harrison

960

Presentation of the Mineralogical Society of America Dana Medal for 2007 to Frank S. Spear
Matthew J. Kohn

961

Acceptance of the Dana Medal of the Mineralogical Society of America for 2007
Frank S. Spear

962

BOOK REVIEWS: Photoatlas of Inclusions In Gemstones, volume 2, by Eduard J. GŸbelin and John I. Koivula. (2005) Opinio Verlag Publishers, Basel, Switzerland. 829 p., over 2200 color plates Classic Areas of British Geology: Glencoe Caldera Volcano, Scotland by B.P. Kokelaar and I.D. Moore, 127 pp. British Geological Survey.
George E. Harlow and Dougal Jerram

713

The crystal structure of vurroite, Pb₂₀Sn₂(Bi,As)₂₂S₅₄Cl₆: OD-character, polytypism, twinning, and modular description
Daniela Pinto, Elena Bonaccorsi, Tonci Balić-Žunić, and Emil Makovicky

765

Quantitative absorbance spectroscopy with unpolarized light: Part II. Experimental evaluation and development of a protocol for quantitative analysis of mineral IR spectra
Istv‡n Kov‡cs, Jšrg Hermann, Hugh St.C. O’Neill, John Fitz Gerald, Malcolm Sambridge, and G‡bor Horv‡th

784

Precise dating of biotite in distal volcanic ash: Isolating subtle alteration using ⁴⁰Ar/³⁹Ar laser incremental heating and electron microprobe techniques
M. Elliot Smith, Brad S. Singer, Alan R. Carroll, and John H. Fournelle

821

Interlayer potassium and its neighboring atoms in micas: Crystal-chemical modeling and XANES spectroscopy
Maria Franca Brigatti, Daniele Malferrari, Marco Poppi, Annibale Mottana, Giannantonio Cibin, Augusto Marcelli, and Gianfelice Cinque

831

Effect of chemical environment on the hydrogen-related defect chemistry in wadsleyite
Yu Nishihara, Toru Shinmei, and Shun-ichiro Karato

880

Biogenic vs. abiogenic magnetite nanoparticles: A XMCD study
Claire Carvallo, Philippe Sainctavit, Marie-Anne Arrio, Nicolas Menguy, Yuheng Wang, Georges Ona-Nguema, and Sandrine Brice-Profeta

893

A 3D reconstruction of plagioclase crystals in a synthetic basalt
Stéphanie Duchêne, Elsa Pupier, Christian Le Carlier De Veslud, and Michael J. Toplis

902

Rudashevskyite, the Fe-dominant analogue of sphalerite, a new mineral: Description and crystal structure
Sergey N. Britvin, Alla N. Bogdanova, Maya M. Boldyreva, and Galina Y. Aksenova

918

Crystal structure of synthetic Al₄B₂O₉: A member of the mullite family closely related to boralsilite
Reinhard X. Fischer, Volker Kahlenberg, Dietmar Voll, Kenneth J.D. MacKenzie, Mark E. Smith, Bernhard Schnetger, Hans-Jürgen Brumsack, and Hartmut Schneider