  Considering the flat rotation curves as input and treating the matter content
in the galactic halo region as quark matter, we have found out a background
spacetime metric for the region of the galactic halo. We obtain fairly general
conditions that ensure that gravity in the halo region is attractive. We also
investigate the stability of circular orbits, along with a different role for
quark matter. Bag-model quark matter meeting these conditions therefore
provides a suitable model for dark matter.
