Titre du document / Document title

Nifontovite and olshanskyite from Fuka, Okayama Prefecture, Japan

Auteur(s) / Author(s)

KUSACHI I. ; HENMI C. ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

Okayama univ., fac. education, dep. earth sci., Okayama 700, JAPON

Résumé / Abstract

Nifontovite and olshanskyite, two rare hydrous calcium borate minerals, have been found in crystalline limestone near gehlenite-spurrite skarns at Fuka, Okayama Prefecture. Nifontovite occurs as aggregates of tabular crystals up to 5 cm long and 1.5 cm wide, and rarely as euhedral crystals up to 1 mm long. Olshanskyite occurs as anhedral masses, or as micro-twinned platy crystals up to 1 cm long. Wet chemical analyses give the empirical formulae Ca_3.052B_5.991O_6.038 (OH)₁₂.1.96H₂O and Ca_2.888B_3.997(OH)₁₈ on the basis of O = 20 for nifontovite and OH = 18 for olshanskyite, respectively. The formulae are consistent with those from type localities. The X-ray powder data for these minerals were determined with accuracy

Revue / Journal Title

Mineralogical Magazine   ISSN 0026-461X   CODEN MNLMBB 

Source / Source

1994, vol. 58, n^o2, pp. 279-284 (10 ref.)

Langue / Language

Anglais

Editeur / Publisher

Mineralogical Society, London, ROYAUME-UNI  (1969) (Revue)

Mots-clés anglais / English Keywords

nifontovite ; olshanskyite ; borates ; skarn ; Japan ; crystal form ; dimensions ; twinning ; structural formula ; X-ray diffraction analysis ; X-ray powder diffraction ; unit cell ; crystal systems ; space groups ; cell dimensions ; density ; hydrothermal alteration ; infrared spectra ; optical properties ; chemical composition ; Asia ;

Mots-clés français / French Keywords

Nifontovite ; Olshanskyite ; Borate ; Skarn ; Japon ; Forme cristalline ; Dimension ; Macle ; Formule structurale ; Diffraction RX ; Diagramme poudre ; Maille élémentaire ; Système cristallin ; Groupe espace ; Constante réticulaire ; Densité ; Altération hydrothermale ; spectre IR ; Propriété optique ; Analyse chimique ; Calcaire cristallin ; Asie ;

Mots-clés espagnols / Spanish Keywords

Nifontovita ; Olshanskyita ; Borato ; Skarn ; Japón ; Forma cristalina ; Dimensión ; Macla ; Difracción RX ; Diagrama polvo ; Celdilla cristalina ; Sistema cristalino ; Grupo espacio ; Constante reticular ; Densidad ; Alteración hidrotermal ; Espectro IR ; Propiedad óptica ; Análisis químico ; Asia ;

Localisation / Location

INIST-CNRS, Cote INIST : 3052, 35400004626827.0100