  A novel measure, quantumness of correlations is introduced here for bipartite
states, by incorporating the required measurement scheme crucial in defining
any such quantity. Quantumness coincides with the previously proposed measures
in special cases and it vanishes for separable states - a feature not captured
by the measures proposed earlier. It is found that an optimal generalized
measurement on one of the parts leaves the overall state in its closest
separable form, which shares the same marginal for the other part, implying
that quantumness is non-zero for all entangled bipartite states and it serves
as an upper bound to the relative entropy of entanglement.
