The crystal-chemistry of riebeckite, ideally Na2Fe23+ Fe-2(3)+ Si8O22(OH)(2) : a mufti-technique study

摘要

In this work we report on a complete crystal-chemical characterization of a near end-member riebeckite from Malawi, and use the available data to critically compare information obtained from different analytical methods. The sample occurs as well-formed and very large single crystals in pegmatitic rocks. Accurate site-populations were determined by combining single-crystal structure refmement and electron microprobe analysis (EMPA). The Fe3+ /Fe2+ ratio was obtained from Mossbauer spectroscopy. Lithium was quantified by Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS).