Geochemical characteristics of muscovite composing the two-mica granite, greisenized facies, the massive greisen and the mineralized veins selvages of Panasqueira. (a) Ternary Ti-Na-Mg diagram displaying the fields of primary and secondary muscovite (after Miller et al., 1981). (b) Compositions of muscovite plotted in the mineralochemical phase diagrams (Al-(Fe + Mg + Mn)-Si) of Monier and Robert (1986). (c) Chemical maps of Al, Ti, Fe and Mg of muscovites composing the greisen of Panasqueira. These muscovites exhibit a strong chemical zoning corresponding to hydrothermal overgrowths of primary magmatic muscovites.