  A wide observational campaign was carried out in 2004-2009 aimed to complete
the ground-based investigation of Lutetia prior to the Rosetta fly-by in July
2010. We have obtained BVRI photometric and V-band polarimetric measurements
over a wide range of phase angles, and visible and infrared spectra in the
0.4-2.4 micron range. We analyzed them together with previously published data
to retrieve information on Lutetia's surface properties. Values of lightcurve
amplitudes, absolute magnitude, opposition effect, phase coefficient and BVRI
colors of Lutetia surface seen at near pole-on aspect have been determined. We
defined more precisely parameters of polarization phase curve and showed their
distinct deviation from any other moderate-albedo asteroid. An indication of
possible variations both in polarization and spectral data across the asteroid
surface was found. To explain features found by different techniques we propose
that (i) Lutetia has a non-convex shape, probably due to the presence of a
large crater, and heterogeneous surface properties probably related to surface
morphology; (ii) at least part of the surface is covered by a fine-grained
regolith with particle size less than 20 microns; (iii) the closest meteorite
analogues of Lutetia's surface composition are particular types of carbonaceous
chondrites or Lutetia has specific surface composition not representative among
studied meteorites.
