Fluorine micas were synthesized using talc and K₂SiF₆ at 900°C for 1 hour in an electric furnace. With increasing K₂SiF₆/talc ratio, b and c unit cell parameters of synthetic fluorine micas were decreased. This result may be interpreted in terms of the shrinkage of the octahedral sheet by the loss of Mg²⁺ from the octahedral site. Infrared absorption spectra of synthetic micas showed the splitting of the absorption band of Si-O stretching, which indicates that some alkali ions migrate into the interlayer site of silicate skeleton. The one dimensional Fourier synthesis showed that with the increase of K₂SiF₆/talc ratio the electron density of K⁺ in the interlayer site of synthetic micas increased and that of Mg²⁺ from the octahedral site decreased. These analytical data indicate that fluorine micas are mainly formed by the transformation from talc without entire disruption of the original atomic arrangement by the intercalation process of alkali ion into the interlayer site of talc and partially formed by solid state reactions. The negative zeta potential of synthetic fluorine micas decreased in magnitude as with increasing K₂SiF₆/talc ratio. It indicates that the zeta potential of synthetic fluorine micas is closely connected with their net layer charge.