  We show a selection of high-sensitivity spectropolarimetric observations
obtained over the last few years in the Ba II D2-line with the Zurich Imaging
Polarimeter (ZIMPOL) attached to the Gregory Coude Telescope of IRSOL. The
measurements were collected close to the solar limb, in several regions with
varying degree of magnetic activity. The Stokes profiles we have observed show
clear signatures of the joint action of the Hanle and Zeeman effects, in very
good qualitative agreement with the theoretical expectations. Polarimetric
measurements of this line show to be very well suited for magnetic field
diagnostics of the lower solar chromosphere, from regions with field
intensities as low as 1 gauss to strongly magnetized ones having kG field
strengths.
