  Current evidence for dark matter in the universe does not exclude heavy
composite nuclear-density objects consisting of bound quarks or antiquarks over
a significant range of masses. Here we analyze one such proposed scenario,
which hypothesizes antiquark nuggets with a range of log10(B) = 24-30 with
specific predictions for spectral emissivity via interactions with normal
matter. We find that, if these objects make up the majority of the dark matter
density in the solar neighborhood, their radiation efficiency in solids is
marginally constrained, due to limits from the total geothermal energy budget
of the Earth. At allowed radiation efficiencies, the number density of such
objects can be constrained to be well below dark matter densities by existing
radio data over a mass range currently not restricted by other methods.
