  The onset of planet formation in protoplanetary disks is marked by the growth
and crystallization of sub-micron-sized dust grains accompanied by dust
settling toward the disk mid-plane. Here we present infrared spectra of disks
around brown dwarfs and brown dwarf candidates. We show that all three
processes occur in such cool disks in a way similar or identical to that in
disks around low- and intermediate-mass stars. These results indicate that the
onset of planet formation extends to disks around brown dwarfs, suggesting that
planet formation is a robust process occurring in most young circumstellar
disks.
