  The features of hot and dense gas of quarks which are considered as the
quasi-particles of the model Hamiltonian with four-fermion interaction are
studied. Being adapted to the Nambu-Jona-Lasinio model this approach allows us
to accommodate a phase transition similar to the nuclear liquid-gas one at the
proper scale and to argue an existence of the mixed (inhomogeneous) phase of
vacuum and normal baryonic matter as a plausible scenario of chiral symmetry
(partial) restoration. Analyzing the transition layer between two phases we
estimate the surface tension coefficient and speculate on the possible
existence of quark droplet.
