  We develop a simple model, in the spirit of the Asakura-Oosawa theory, able
to describe the effects of surface roughness on the depletion potential as a
function of a small set of parameters. The resulting explicit expressions are
easily computed, without free parameters, for a wide range of physically
interesting conditions. Comparison with the recent numerical simulations [M.
Kamp et al., Langmuir, 2016, 32, 1233] shows an encouraging agreement and
allows to predict the onset of colloidal aggregation in dilute suspensions of
rough particles. Furthermore, the model proves to be suitable to investigate
the role of the geometry of the roughness.
