  We show that the expected lifetime of white holes formed as remnants of
evaporated black holes is consistent with their production at reheating. We
give a simple quantum description of these objects and argue that a quantum
superposition of black and white holes with large interiors is stable, because
it is protected by the existence of a minimal eigenvalue of the area, predicted
by Loop Quantum Gravity. These two results support the hypothesis that a
component of dark matter could be formed by small black hole remnants.
