.... The specimens are labeled as type manjiroite, but our analyses show that Na is not the dominant tunnel species, nor is it even the primary tunnel cation, suggesting either an error in the original analyses or significant compositional variation within samples from the type locality. Chemical analyses, X-ray...

...J. Gutzmer; Nicolas J. Beukes Abstract Asbestiform manjiroite and todorokite occur as infill of bedding parallel extension veinlets in supergene altered braunite-kutnahorite lutite at the Smartt Mine in the Kalahari manganese field, South Africa. Geological evidence and preliminary geochronological...

... in the mineralized zones and formation of a 1.2-m-wide quartz-fluorapatite-manjiroite vein (9.95 wt % P 2 O 5 ). Samples of manganite and pyrolusite often contain vug fillings and inclusions of rhodochrosite and minor amounts of other hypogene minerals such as knebelite and pinakiolite. Furthermore, these samples...

..., hollandite, lithiophorite, manganite, manganese(III) manganate(IV), manganosite, manjiroite, marokite, nsutite, partridgeite, pyrolusite, quenselite, rancieite, ramsdellite, ro-manechite, sodium manganese(II,III) manganate(IV), todorokite, and woodruffite. The spectra indicate that well-ordered water occurs...

...-grained acicular cryptomelane crystals that are orientated perpendicular to the host fracture surface. §   Corresponding author e-mail address : [email protected] 13 June 2017 8 November 2017 © 2018 Mineralogical Association of Canada 2018 Cryptomelane manjiroite...

... & Wadsley (1950) Manjiroite I 4/ m a = 9.916, c = 2.864 Å Nambu & Tanida (1967) Strontiomelane P 2 1 / n a = 10.00, b = 5.758, c = 9.88 Å, β = 90.64° Meisser et al. (1999) Priderite group (M 4+ = Ti) Priderite I 4/ m a = 10.139, c = 2.966 Å Post et al...

... perplexity, two of these authors have invoked some of the same textural evidence to validate their interpretation of a crack-seal origin for asbestiform manjiroite and todorokite veins in altered braunite-kutnahorite lutites from the Kalahari manganese field of South Africa ( Gutzmer and Beukes, 2000...

... x (H 2 O) 2− x ] (Ti 8−2 x V 3+ 2 x )O 16 , manjiroite (Na,K)(Mn 4+ ,Mn 2+ ) 8 O 16 · nH 2 O, and cesarolite PbH 2 Mn 3 O 8 . In 1978, Zhuravleva et al. found a new mineral in carbonatites from the Kovdor massif with the chemical formula (Ba 0.7 K 0.1 )(Fe 1.1 Ti 6.9 )O 16 , which...

...° [14] Priderite, K(Ti,Fe 3+ )O 16 I 4/ m a 10.139, c 2.966 Å [12] Akaganéite, FeO(OH) I 2/ m a 10.587, b 3.031, c 10.515 Å, β 90.03° [15] Manjiroite, (Na,K)(Mn 4+ ,Mn 3+ ) 8 O 16 I 4/ m a 9.916, c 2.864 Å [16] Strontiomelane, SrMn 4+ 6 Mn 3+ 2 O 16 P...

... ) Manjiroite, a new manganese dioxide mineral, from Kohare Mine, Iwate Prefecture, Japan . The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists , 58 , 39 – 54 ( in Japanese ). Nawrocki , J. , Polechońska , O. , Lewandowska , A. , and Werner , T...

...Figure 10. Raman spectra (532 nm) for manjiroite (S. Africa), cryptomelane (no. 2236-1), hollandite (NM), and coronadite (no. 106257). The crystal elongation directions were oriented parallel to the incident beam polarization. ...

.../manjiroite occurrences of supergene origin described in detail in the MKD ( Gutzmer and Beukes, 2000 ). Friedelite, with the approximate chemical formula Mn 2+ 8 Si 6 O 15 (OH, Cl) 10, is a phyllosilicate mineral belonging to the pyrosmalite group ( Ozawa et al., 1983 ). Friedelite occurs primarily...

... . Acta Crystallogr. , 13 , 164 – 165 . Nambu M. Tanida K. ( 1967 ): Manjiroite, a new manganese dioxide mineral, from Kohare Mine, Iwate Prefecture, Japan . J. Jpn. Ass. Mineral. Petrol. Econ. Geol. , 58 , 39 – 54 (in Japanese). Orlandi P. ( 1984 ): Segnalazione di nuove...