  We propose a modified metric based on the Hilbert-Schmidt norm and adopt it
to define a rescaled version of the geometric measure of quantum discord. Such
a measure is found not to suffer from the pathological dependence on state
purity. Although the employed metric is still noncontractive under quantum
operations, we show that the resulting indicator of quantum correlations is in
agreement with other bona fide discord measures in a number of physical
examples. We present a critical assessment of the requirements of reliability
versus computability when approaching the task of quantifying, or measuring,
general quantum correlations in a bipartite state.
