Descripción de la macla de la frondelita-rockbridgeita asociada a las pegmatitas del Macizo de L´Arize, Pirineos (Ariege).

• F. Fontan ^[1] ; E. Roda ^[2]
  1. [1] Paul Sabatier University

     Paul Sabatier University

     Arrondissement de Toulouse, Francia

     
  2. [2] Dpto. Mineralogía y Petrología, Universidad del País Vasco/EHU, Apdo. 644, 48080 Bilbao.
• Localización: Geogaceta, ISSN 0213-683X, Nº. 20, 7, 1996, págs. 1524-1526
• Idioma: español
• Títulos paralelos:
  • Description of twin in frondelite-rockbridgeite associated with the pegmatites of the L´Arize Massif (Pirinees, Ariege).
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• Resumen

  • A cruciform intergrowth in a phosphate of the frondelite-rockbridgeite series associated with beryl-columbite pegmatites is studied on the basis of geometric considerations. The crystallographical calculations prove, for the first time, the existence of a reticular pseudomeroedric twinning in frondelite, having as twin plane the (041), an obliquity of =3 and a twin index =7, which may explain the rarity of this twinning.