Acta Musei Moraviae

Wolframite from heavy-mineral assemblages at Trucbába – Valcha, Moldanubicum

Magnesium-rich wolframite from stream sediment in Trucbába – Valcha locality (Humpolec area) was found. It forms sporadic black grains among ilmenite, magnetite, monazite-(Ce), xenotime-(Y), scheelite, garnet, rutile, zircon, apatite, sillimanite, tourmaline, cassiterite and gold in the heavy-mineral concentrates. In the wolframite dominates ferberite (77–86 %) component over both huanzalaite (≤ 11 %) and hübnerite (6–10 %) components. Other analyzed elements are near (e. g. Bi, Ca, Nb, Sc, Ti, Zr) or bellow (Na, Pb, Sb, Sn, Ta, U, Y) detection limits. Primary wolframite-bearing occurrences in surrounding Moldanubicum contain scheelite-, cassiterite- and elsewhere gahnite mineral assemblages. Their wolframites are poor in Mg, therefore primary locality of Mg-rich ferberite studied remain unknown.