...Hiromi Konishi; Huifang Xu; Robert F. Dymek Abstract Jimthompsonite and chesterite occur as intergrowths within anthophyllite up to a few millimeters across in talc-magnesite schist from the ~3800 Ma Isua Supracrustal Belt, West Greenland. Pyribole lamellae span the entire intergrowth width...

...Hiromi Konishi; Peter R. Buseck; Huifang Xu; Xiaochun Li Abstract Proto-polymorphs of jimthompsonite and chesterite occur in metamorphosed serpentinites from two Japanese ultramafic complexes. The lattice constants of the proto triple-chain silicate, measured by X-ray diffraction, are a = 0.93605...

...D. R. Veblen; C. W. Burnham Abstract The crystal structures of jimthompsonite, clinojimthompsonite, and chesterite have been solved and refined using three-dimensional X-ray intensity data. Jimthompsonite and clinojimthompsonite contain I-beams composed of triple silicate chains and wide octahedral...

...F igure 6. Change of chesterite to a 2111 chain sequence by irradiation for 20 min. The chesterite was amorphized along the fracture and perhaps on the surface of the grain (top: before experiment; bottom: after experiment). In top image, the larger white dots indicate triple chains, whereas...

...D. R. Veblen; P. R. Buseck Abstract High-resolution с -axis images of the biopyribole minerals anthophyllite [(Mg,Fe) 7 Si 8 O 22 (OH) 2 ], jimthompsonite [(Mg,Fe) 10 Si 12 O 32 (OH) 4 ], and chesterite [(Mg,Fe) 17 Si 20 O 54 (OH) 6 ] have been produced in the transmission electron microscope...

.... The cell parameters of the minerals are diagnostic: (1) jimthompsonite is orthorhombic, Pbca, a = 18.6, b = 27.2, с = 5.30A; (2) clinojimthompsonite is monoclinic, C 2/ c, a = 9.87, b = 27.2, с = 5.32A, β = 109.5°; (3) chesterite is orthorhombic, A 2 1 ma, a = 18.6, b = 45.3, с = 5.30A; (4) an unnamed...

...Fig. 10 The structure of chesterite simplified: octahedral cations are shown with the same size, ignoring chemical differences due to the different isomorphic substitutions. By ignoring the octahedral atoms in blue, the structure of chesterite appears built by a regular alternation of Z 8 and Z...

...Fig. 15 A schematic view of the structure of chesterite along the c axis, where the Z 8 and Z 5 modules are replaced by larger A and smaller B rectangles. Partial operations map A to A and B to B, whereas transmutation operations map A to B but not B to A. Thin-line rectangle is the unit cell...

... ) Φ 0 − 2 ( N − 1 ) t ] This expression also generates mixed-ribbon polysomatic structures. Thus S (1;2+3) gives the chemical composition and structure of the mixed-chain pyribole chesterite, and S (2;1+4) gives the chemical composition and structure of the mixed-chain H–O–H mineral, veblenite...

...) with composition near that of talc, (Mg,Fe) 3 Si 4 O 10 (OH) 2 . The calculations were performed using results of the structure refinements of two orthopyroxenes (Opx), clinoenstatite (Cpx), twoampiboles (anthophyllite = An, cummingtonite = Cu), chesterite (Ch), jimthompsonite (Jt), clinojimthompsonite, and talc...

...John C. Schumacher; Michael Czank Abstract Pyriboles that consist of mixed double chains (anthophyllite), alternating double and triple chains (chesterite), and triple chains (jimthompsonite) coexist with phlogopite and Zn-rich spinel at Orijärvi, southwestern Finland. Each of these three pyribole...