  We consider the antiferromagnetic Heisenberg model on a distorted diamond
chain and use the localized-magnon picture adapted to a distorted geometry to
discuss some of its high-field low-temperature properties. More specifically,
in our study we assume that the partition function for a slightly distorted
geometry has the same form as for ideal geometry, though with slightly
dispersive one-magnon energies. We also discuss the relevance of such a
description to azurite.
