  The profile of the silicate 10 $\mu$m IR band contains important information
about the evolutional stage of dust in circumstellar environments and the
possible ongoing process of planetesimal formation. In order to extract this
information, the observed band profiles are compared with calculated or
laboratory-measured absorption cross sections of amorphous and crystalline
grains with different sizes and compositions. We present in this study the
first laboratory measurements of the 10 $\mu$m band profiles of nonembedded,
i.e. free-flying, particles of amorphous and crystalline Mg$_2$SiO$_4$ (with
two different particle shapes), amorphous and crystalline MgSiO$_3$, and
crystalline olivine. We compare the spectra with those measured on embedded
grains and discuss the potential of the new experimental method for comparison
with observed spectra, as well as for future studies of agglomeration and
surface manipulation of the grains.
