Fluid inclusions from the vein quartz near Velká Kraš have been investigated. Inclusions with two immiscible liquids, aqueous (L1) and carbonic (L2) one, have been found so far. Most of inclusions have a stable ratio of both liquids (L2/L1 = 0.1). Based on petrographic observation we could state that fluids might be trapped close to the one phase and two phase boundary of the H2O-NaCl-CO2 system. The two cogenetic fluid inclusions, with immiscible CO2-rich and H2O-rich fluid phases, have been used for an estimation of the p-T conditions. The temperature 320 °C and presure 2 050 bars could be a lower limit for the precipitation of the quartz. The salinity of the aqueous solution is 4.5 mass. % NaCl eq. The trapped fluids show a nature of the pegmatite post-magmatic solutions
