  The ZnWO$_4$ is an anisotropic crystal scintillator; for its peculiar
characteristics, it is a very promising detector to exploit the so-called
directionality approach in the investigation of those Dark Matter (DM)
candidates inducing nuclear recoils. Recently, in the framework of the ADAMO
project, an R\&D to develop high quality and ultra-radiopure ZnWO$_4$ crystal
scintillators has been carried out. In the present paper the measurements to
study the anisotropic response of a ZnWO$_4$ to $\alpha$ particles and to
nuclear recoils induced by neutron scattering are reported. Monochromatic
neutrons have been produced by a neutron generator at ENEA-CASACCIA. The
quenching factor values for nuclear recoils along different crystallographic
axes have been determined for three different nuclear recoils energies. These
results open the possibility to realize a pioneer experiment to investigate the
above mentioned DM candidates by means of the directionality.
