Mass fraction of emitted solid-ice particles as a function of the VFF when applying the geometrical model to the measured particle size distribution of the micro-granular water-ice sample (Kreuzig et al. 2023). Due to the inherent randomness of the sphere placements, five simulations were performed for each VFF. Also shown is a fit to the data that surpasses a dust-emission efficiency of unity at a VFF of ∼0.15 and has been set to 1 for smaller VFF values. The fitting function that was used is y(x) = (x − x₀)^a ⋅ 10^b, with the values a = −1.449, b = −2.185, and x₀ = 0.117.