  The transition from the 1/3 magnetization plateau towards the saturation
magnetization in azurite has been studied by low-temperature,
high-magnetic-field, high-frequency proton nuclear magnetic resonance (NMR).
The observed symmetrical splitting of the NMR spectra is incompatible with the
longitudinal incommensurate order appearing when the longitudinal correlation
function becomes dominant over the transverse one, which is the expected
framework for the existence of the 2/3 magnetization plateau. The spectra are
rather interpreted in terms of a more standard transverse antiferromagnetic
(canted) order.
