  We investigate the hypothesis that sexaquarks, hypothetical stable six-quark
states, could be a significant component of the dark matter. We expand on
previous studies of sexaquark cosmology, accounting for the possibility that
some relevant interaction cross sections might be strongly suppressed below
expectations based on dimensional analysis. We update direct-detection
constraints on stable sexaquarks comprising a subdominant fraction of the dark
matter, as well as limits on the annihilation of an antisexaquark component
from Super-Kamiokande. We argue that the scenario where sexaquarks comprise a
$O(1)$ fraction of the dark matter would require either a suppression of
$O(10^{-19})$ in sexaquark interactions with baryons, combined with a very high
yield of net sexaquark number from the quark-hadron transition, or else a very
strong suppression of the cross section for antisexaquark annihilation on
nucleons (24+ orders of magnitude below the QCD scale). Independently, we find
that a sexaquark component comprising more than $O(10^{-3})$ of the dark matter
can be excluded from direct-detection bounds, unless its scattering cross
section is severely suppressed compared to the expected scale of strong and
even electromagnetic interactions.
