The compositions of trioctahedral micas from 51 samples of granitoids with different geochemical affiliations and grades of differentiation from the Bohemian Massif, Central Europe, were analysed using electron microprobe (major elements) and laser ablation inductively coupled plasma mass spectrometry (Li, Sc, Ga, Ge, Nb, In, Sn, Cs, Ta, W, Tl). The micas form a continuous evolutionary series from phlogopite to zinnwaldite. The phlogopites and biotites from the I-type rocks are characterized by 5.5–5.7 Si, 2.4–2.6 Al, <0.1 Li atoms per formula unit [apfu] and Mg/(Mg + Fe) = 0.4–0.8. The biotites from the S-type granites usually contain 5.3–5.7 Si, 3.2–3.6 Al, 0.1–0.3 Li apfu and Mg/(Mg + Fe) = 0.15–0.4. The annites and zinnwaldites from the rare-metal granites contain 5.7–6.8 Si, 3.2–3.8 Al, 0.6–2.6 Li apfu and Mg/(Mg + Fe) < 0.1. The concentrations of F, Rb, Cs and Tl increase from the phlogopites and biotites to zinnwaldites: F 0.1 → 8 wt.%, Rb2O 0.05 → 1.7 wt.%, Tl 2 → 50 ppm and Cs 40 → 2000 ppm. The concentrations of Sn, Nb, Ta and W in phlogopites and biotites from the I- and S-type granitoids generally correlate with those of the parent rocks and reach values of (in ppm) 20–100 Sn, 20–250 Nb, 1–20 Ta and <5 W. The highest concentrations were found in the Li-annites in the relatively early facies of rare-metal granites (in ppm): 250–600 Sn, 400–600 Nb, 60–120 Ta and 50– 120 W. The zinnwaldites in the late rare-metal granites facies are impoverished in these elements, which is explained by contemporaneous crystallization of cassiterite and columbite. Lithium enters the crystal lattice of trioctahedral micas via the exchange vector Li3□Si3Fe–6Al–1 up to concentrations of ∼2.5 wt.% Li2O (1.5 apfu Li). At higher Li concentrations, Li is incorporated through the exchange vector Li3Si1□–1 Fe–2Al–1.

Zircon from 14 representative granite samples of the late-Variscan Cornubian Batholith in SW England was analysed for W, P, As, Nb, Ta, Si, Ti, Zr, Hf, Th, U, Y, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, Al, Sc, Bi, Mn, Fe, Ca, Pb, Cu, S and F using electron probe microanalyses. Zircons from the biotite and tourmaline granites are poor in minor and trace elements, usually containing 1.0–1.5 wt.% HfO2, <0.5 wt.% UO2 and P2O5, <0.25 wt.% Y2O3, <0.2 wt.% Sc2O3 and Bi2O3 and <0.1 wt.% ThO2. Zircon from topaz granites from the St. Austell Pluton, Meldon Aplite and Megiliggar Rocks are slightly enriched in Hf (up to 4 wt.% HfO2), U (1– 3.5 wt.% UO2) and Sc (0.5–1 wt.% Sc2O3). Scarce metamictized zircon grains are somewhat enriched in Al, Ca, Fe and Mn. The decrease of the zircon Zr/Hf ratio, a reliable magma fractionation index, from 110–60 in the biotite granites to 30–10 in the most evolved topaz granites (Meldon Aplite and Megiliggar Rocks), supports a comagmatic origin of the biotite and topaz granites via long-lasting fractionation of common peraluminous crustal magma. In comparison with other European rare-metal provinces, the overall contents of trace elements in Cornubian zircons are low and the Zr/Hf and U/Th ratios show lower degrees of fractionation of the parental melt.