  We investigate the correlation properties of separable two qubit states with
maximally mixed marginals. These states are divided to two sets with the same
geometric quantum correlation. However a closer scrutiny of these states
reveals a profound difference between their quantum correlations as measured by
more probing measures. Although these two sets of states are prepared by the
same type of quantum operations acting on classically correlated states with
equal classical correlations, the amount of final quantum correlation is
different. We investigate this difference and trace it back to the hidden
classical correlation which exists in their preparation process. We also
compare these states with regard to their usefulness for entanglement
distribution and their robustness against noise.
