QCD Relics of Astrophysical Relevance

The connection between effective-actions and generalizations of Nambu-Jona-Lasinio models is discussed. We suggest the possibility of creation in the early Universe of stable domains of radius a few kilometers wide. Such domains should appear dark to an external observer. The insulation of the domains from the outer world, a consequence of the joint role played by gravity and the existence of two orthogonal Fock spaces could have allowed them to survive untill present days.