  Dark matter direct (and indirect) detection experiments usually can only
determine a specific combination of a power of the coupling and the dark matter
density. This is also true for axion haloscopes which are sensitive to the
product $g^{2}_{a\gamma\gamma}\rho_{\rm DM}$, the combination of axion-photon
coupling squared and the dark matter density. In this note we show, that in the
lucky case when we intersect with a so-called axion minicluster of a suitable
size, we can utilize the spectral information available in haloscopes to
determine the gravitational potential of the minicluster. We can then use this
to measure separately the coupling and the density of the minicluster.
