..., of a single crystal of Mg-sursassite, Mg 5 Al 5 Si 6 O 21 (OH) 7 . In situ high-pressure and high-temperature single-crystal diffraction allowed the study of structural variation at non-ambient conditions and the determination of bulk elastic properties. The refined parameters of a second-order Birch...

...Luca Bindi; Mark D. Welch; Aleksandra A. Bendeliani; Andrey V. Bobrov Abstract The crystal structure of a new high-pressure hydrous phase, Si-rich Mg-sursassite, of ideal composition Mg 4 Al 5 Si 7 O 23 (OH) 5 , that was produced by sub-solidus reaction at 24 GPa and 1400 °C in an experiment using...

...Mariko Nagashima; Masahide Akasaka; Tetsuo Minakawa; Eugen Libowitzky; Thomas Armbruster Abstract The crystal chemistry of sursassite, simplified formula Mn 2 2+ Al 3 Si 3 O 11 (OH) 3 , from six different localities [(1) Falotta, Switzerland, (2) Woodstock, New Brunswick, Canada, (3) Kamisugai...

.... The weight loss from TG measurement is 7.7 wt% at 1000 °C, most of which is interpreted to be due to the loss of structural OH groups. The crystal structure of macfallite [ a = 8.959(3), b = 6.072(2), c = 10.218(4) Å, β = 110.75(3)°, space group P 2 1 / m ], which is isostructural with sursassite...

...Frédéric Hatert; Andre-Mathieu Fransolet; Johan Wouters; Heinz-Jürgen Bernhardt Abstract Sursassite occurs as orange-red needles associated with nsutite, hematite, apatite-(CaF), spessartine, manganoan clinochlore, and ardennite in quartz veinlets cross-cutting the red-purple schists...

...Bernd WUNDER; Matthias GOTTSCHALK Abstract Sursassites (Fe,Mg) 4 (Mg,Al,Fe) 2 Al 4 [Si 6 O 21 / (OH) 7 ] have been synthesized along the Mg-Fe join at 4.0 - 5.0 GPa, 600 - 650 °C and at f 02 defined by the iron-wuestite buffer using gels as starting materials. (Fe,Mg)-sursassites have been...

... been determined by the Rietveld method, and found to be isostructural with sursassite rather than pumpellyite. This phase is therefore a slightly modified Mg-analogue of sursassite Mn 2+ 4 Al 2 Al 4 [Si 6 O 22 /(OH) 6 ], with Mg for Mn and one Al replaced by Mg+H. For material synthesized at 5 GPa...

...R. L. Freed Abstract The geology and mineralogy of sursassite from New Brunswick have been described by Heinrich (1962). Sursassite from the only other known locality, Oberhalbstein, Graubünden, Switzerland, has been analyzed chemically by Müller (1916), Jakob (1926, 1931, 1933), and de Quervain...

...E. William Heinrich Abstract Sursassite, previously known only from Oberhalbstein, Graubunden, Switzerland, occurs in veinlets cutting Middle Silurian Fe-Mn ores about 5 mi W. of Woodstock, New Brunswick. The composition based on a new analysis is Mn 9 Al 4 (Si,Al) 12 O 39 .6H 2 O. Associated...

... be described as layers of X-octahedra shifted by (1/2,0,0) vectors. The shifted layers locally show a sursassite-type arrangement. No disorder was detected in the Y-octahedra, which are fully occupied by Al ions, and in the W positions, commonly hosting sevenfold-coordinated Ca atoms in naturally occurring...

..., and at higher pressures up to 4 GPa pyrope forms from chlorite + talc + kyanite. Beyond 4 GPa, the assemblage talc + chlorite + Mg-chloritoid defines the lower temperature limit around 600 °C. At pressures higher than 5 GPa, pyrope forms via the reactions low-clinoenstatite + chlorite + Mg-sursassite = pyrope...