We discuss the cosmological implications as well as possible observability of
massive, stable, colored particles which often appear in the discussion of
physics beyond the standard model. We argue that if their masses are more than
a few hundred GeV and if they saturate the halo density and/or occur with
closure density of the universe, they are ruled out by the present WIMP search
experiments as well as the searches for anomalous heavy isotopes of ordinary
nuclei. We then comment on the possibility that these particles as well as the
monopoles could be responsible for the ultra high energy cosmic rays with
energy ≥1020 eV and point out that their low inelasticity argues
against this.Comment: 9 pages; UMD-PP-98-1