  If quark matter is energetically favored over nuclear matter at zero
temperature and pressure then it has long been expected to take the form of
strange quark matter (SQM), with comparable amounts of $u$, $d$, $s$ quarks.
The possibility of quark matter with only $u$, $d$ quarks ($ud$QM) is usually
dismissed because of the observed stability of ordinary nuclei. However we find
that $ud$QM generally has lower bulk energy per baryon than normal nuclei and
SQM. This emerges in a phenomenological model that describes the spectra of the
lightest pseudoscalar and scalar meson nonets. Taking into account the finite
size effects, $ud$QM can be the ground state of baryonic matter only for baryon
number $A>A_\textrm{min}$ with $A_\textrm{min}\gtrsim 300$. This ensures the
stability of ordinary nuclei and points to a new form of stable matter just
beyond the periodic table.
