This thesis is focused on detailed description and geochemistry
of the mineral, that belongs to the
betafite group. Betafite occurs in the metacarbonate rock found
in the graphite mine Václav situated in
the village of Bližná. The research part of the thesis
describes the geological surroundings, mineral
assemblages of locality and other localities with similar
geological signature. It contains summary of
carbonatites and pyrochlore supergroup minerals which normally
site in these rocks. The chemical
composition of betafite was detected by electron microprobe
analyzes and it is quite unusual for its Th
and REE-enrichment and very low Ta, Ca, Na and F.