Abstract
Chemical and physical data for five manganoan zinnwaldites from Japan were analysed and were found to be high in fluorine, reflecting the crystallization under relatively high f (HF or F2) conditions. All specimens belong to 1M polytype. The role of fluorine on the formation of 1M type of mica structure was considered. Tetrahedral rotation angles α of five zinnwaldites were calculated from powder data.
