The mechanical properties of spherical alumina and zeolite particles were measured to provide an insight to their susceptibility to milling in a pin-mill. Nanoindentation was applied to determine Young’s modulus and hardness, whilst microindentation and SEM observation were carried out to measure fracture toughness. Preliminary indents determined the suitable load to apply for each material. The Young’s modulus, hardness and fracture toughness were found to be greatest for alumina, and increased with size of zeolite particles. Large scatter was present in the measurements, as is typically the case. The scatter was greater for the zeolite particles than the alumina. The mechanical and physical properties of these particles lead to the prediction that the larger zeolite is more prone to impact breakage caused by a pin mill, with the alumina particles being least susceptible. The impact breakage of the smaller zeolite particles was assessed in a single particle impact rig at a range of impact velocities and angles. The extent of breakage was shown to correlate with normal impact velocity, regardless of impact angle. This is expected to be the case for larger zeolite particles, however alumina particles should be subjected to similar tests to assess if impact angle is influential on the extent of breakage.