  The mixed spin-1/2 and spin-1 Ising model in the presence of an anisotropic
crystalline field is treated exactly within the framework of an extended
star-triangle mapping transformation. The exact results for the phase diagrams,
magnetization, internal energy and specific heat are derived and discussed in
detail. The relevant mapping suggests that an isotropic in-plane crystal field
(D^x = D^y) leads to the same effects as the hard-axis crystal field (D^z),
whereas the in-plane anisotropy (D^x \neq D^y) is responsible also for the
randomization of the magnetic ordering (transverse-field like effect).
